How Politicized Judicial Nominations Affect Attitudes
toward the Courts: Evidence from a Conjoint
Experiment∗
Jon C. Rogowski†
Harvard University
Andrew R. Stone‡
Harvard University
March 31, 2017
Abstract
Supreme Court nominations are unavoidably, and perhaps inevitably, political. Though
legal scholars, court observers, and justices themselves express concern that politicized nominations undermine support for qualified nominees and threaten the Court’s legitimacy, extant
scholarship provides little empirical evidence to address these claims. We argue that politicization polarizes partisans’ attitudes toward nominees and the Court more generally. We
present data from a conjoint experiment embedded in a nationally representative survey of
2,500 U.S. adults administered in the first days of the Trump presidency to test these claims.
While exposure to politicized rhetoric from President Trump and Senate Democrats has no
aggregate effect on public opinion, we find that politicization significantly increases support
among the president’s copartisans but reduces support from the opposite party. Politicization
also generates significant partisan differences in assessments of the Court’s legitimacy, suggesting that the Court’s institutional strength is vulnerable to political contestation among
actors in other branches of government.
We thank Stephen Ansolabehere, Dino Christenson, Chase Harrison, and Andrew Reeves for helpful comments
and the Faculty of Arts and Science at Harvard University for research support.
†
Assistant Professor, Department of Government, 1737 Cambridge St, Cambridge, MA 02138; rogowski@fas.
harvard.edu.
‡
Ph.D. Student, Department of Government, 1737 Cambridge St, Cambridge, MA 02138; [email protected].
∗
The U.S. Supreme Court — and public opinion towards it — sits uniquely among American
political institutions. In contrast with presidents and legislators, justices depict themselves as
neutral arbiters of the law, ruling without regard to their political views. Persistently high levels of
legitimacy of the U.S. Supreme Court have been well documented by judicial scholars, and support
for the Supreme Court remains remarkably stable over time while trends in public approval of
the presidency and Congress oscillate with the political winds.1 In the separation of powers
system, the importance of a strong and independent judiciary for curbing executive and legislative
ambition (Federalist #78; Moe and Howell 1999) coupled with the judiciary’s lack of enforcement
powers generates persistent concern about circumstances that could erode its support.
In modern times, the politicization of the Supreme Court nomination process presents challenges for the appointment of well-qualified justices and has been regarded as a particularly acute
threat to the Court’s legitimacy. On this issue there has been broad agreement across the partisan aisle. After nominating Merrick Garland in 2016 to fill the seat vacated upon Justice Antonin
Scalia’s death, President Obama lamented the Senate’s refusal to hold a confirmation vote for
“an extraordinary jurist who is indisputably qualified to serve on the highest court of the land.”2
None other than Neil Gorsuch, nominated for the same vacancy by President Trump, had earlier recognized Merrick Garland as “among the finest lawyers of his generation” who had been
“grossly mistreated” by the Senate when nominated by President George W. Bush to serve on the
U.S. Court of Appeals.3 The millions of dollars spent by interest groups on advertising campaigns
supporting and opposing Court nominees and the stark partisan divides that frequently emerge
in support for nominees threaten the Court’s legitimacy if the public begins to equate judges
with “ordinary politicians” (Gibson and Caldeira 2009a, 2011). These concerns are widely shared,
1 For
a review of the literature on legitimacy and the Supreme Court, see Gibson and Nelson (2014).
Geiger and Rick Pearson, “Obama makes his case at U. of C. for Supreme Court nominee,” April 7, Chicago
Tribune; available at http://www.chicagotribune.com/news/local/breaking/ct-obama-merrick-garland-universityof-chicago-20160407-story.html (accessed March 31, 2017).
3 Neil Gorsuch, “Justice White and judicial excellence,” May 4, 2002, UPI ; available at http://www.upi.com/JusticeWhite-and-judicial-excellence/72651020510343/ (accessed March 31, 2017).
2 Kim
1
with Obama worrying that the infusion of partisanship into judicial appointments “erodes the
[Court’s] institutional integrity” and Chief Justice Roberts arguing that the modern nomination
process leads the public to view the Court and its members in partisan and ideological terms.4
In this paper, we examine how politicized judicial nominations affect Americans’ attitudes
toward Supreme Court nominees and perceptions of the Court’s legitimacy. Despite widespread
concern about the potential consequences of politicization, existing scholarship provides little
direct evidence of its effects. In studying how politicization affects public opinion toward Court
nominees, we build on insights from previous research on individual-level support for Supreme
Court nominees (Caldeira and Smith 1996; Gimpel and Wolpert 1996; Sen Forthcoming) to understand how politicized nominating procedures shape the incentives for Senate confirmation
votes (see, e.g., Kastellec, Lax, and Phillips 2010). And while other studies investigate the effects
of politicized selection processes on judicial legitimacy (Gibson and Caldeira 2009a; Gibson 2009,
2012), this body of scholarship focuses largely on state-level judicial elections and, when considering judicial nominations to the federal bench, centers on the effects of interest group advertising.
Thus, scholarship provides little evidence as to how the politicization of the nomination process
by elected officials — in particular, Senators and the president — shape attitudes toward judicial
nominees and the Court more generally. Understanding the interplay between elected officials
and judicial nominees is important for characterizing the capacity of political actors to shape
public opinion toward the adjoining branches of government.
Extending research on attitudes toward the judiciary and the role of partisanship in opinion
formation, we develop a theory about how politicized rhetoric from Senators and the president
shapes individual-level support for judicial nominees and the Court more generally. We argue
that the politicization of judicial nominations reminds the public of the political nature of the
Court and subsequently produces a partisan response from the American public. By eliciting
4 See Roberts’ remarks on the nomination process after the death of Justice Antonin Scalia here: https://www.cspan.org/video/?404131-1/discussion-chief-justice-john-roberts (accessed March 26, 2017).
2
more favorable opinions from the president’s copartisans and more negative opinions among individuals who identify with the opposite party, our argument predicts that politicization polarizes
American public opinion toward the president’s judicial nominees and the Court as a whole.
We assess our argument with data from a conjoint experiment embedded on a nationally representative survey of 2,500 U.S. adults. The experiment was conducted during the first week of the
Trump presidency and asked respondents to evaluate potential nominees for the open Supreme
Court seat inherited by President Trump. Our results demonstrate that politicized messages led
Republicans to provide greater support for the prospective nominee and diffuse support for the
Court, but these same messages led to declines among Democrats. We further find that the effects
of politicization do not depend on the specific content of the messages; instead, they appear to be
generated in response to the nature of the partisan actors sending the messages. We find limited
evidence that the effects of politicization are conditioned by judicial knowledge and no evidence
that its effects are moderated by either respondents’ favorability toward the Court, attentiveness
to the Court’s vacancy, or importance assigned to the identity of the next justice.
Taken together, our results suggest that overtly political Supreme Court nominations may
have deleterious effects for judicial legitimacy and attitudes toward Supreme Court justices. In
particular, and in contrast to existing research regarding partisan attitudes toward the Court
(Gibson 2007), we find evidence of a polarization in attitudes toward the Court as a function of
politicized elite rhetoric. This suggests the potential for contentious nominations to have negative effects on those subsets of the electorate most critical to ensuring compliance with the
Court’s rulings — those that disagree with its decisions on ideological grounds (Gibson 2015;
Nadeau and Blais 1993; Sullivan, Piereson, and Marcus 1982). Our results further suggest that
the Court’s institutional strength is vulnerable to politicized attacks from the other branches of
government, raising important implications about the consequences of rhetoric for the erosion
of judicial power. Finally, our results highlight the ubiquity of partisanship for structuring contemporary American public opinion, with the courts no exception to partisan influences.
3
Public Attitudes and Supreme Court Nominations
The courts have long been understood as distinct from the executive and legislative branches
of government. At a fundamental level, the institutions are structured in considerably different
ways: federal judges are appointed, not popularly elected, and serve life terms subject to good
behavior. Norms of practice on the federal courts, including the political question doctrine and
unanimous opinion writing on the appellate courts, mean the courts rarely wade into explicitly
political territory with their decisions. Even the visual cues associated with the courts, such as
judges’ robes and symbols of justice, convey the uniqueness of the judiciary among the branches
of government (Gibson, Lodge, and Woodson 2014).
Despite these distinctions, the courts and the legislative and executive branches are inexorably
connected through the nomination process. Article II of the U.S. Constitution gives the president
and Senate the power to nominate and confirm Supreme Court justices, respectively, making the
nomination process one of the few circumstances in which all three branches of government are
explicitly intertwined. While the Founders saw the advice and consent process as an important
check on executive power (Federalist #76), contrasting executive and legislative preferences over
judicial nominees can have the byproduct of bringing overtly political fights into the ordinarily
legalistic and apolitical judiciary. We refer to this concept as the politicization of the judiciary: the
introduction of the familiar partisan and ideological disagreements that animate politics within
the executive and legislative branches to the judicial arena.5
Though contemporary judicial nominations may be more politicized than they ever have
been, partisan nomination fights, especially over those to the Supreme Court, have been common since the nation’s early years.6 For instance, after being nominated to the Supreme Court by
5 The
concept of politicization has been studied extensively in contexts outside of the judiciary. For instance,
the content of campaign advertisements has been increasingly ideological and negative in modern elections (e.g.,
Jamieson 1993; Lau et al. 1999), legislators employ the congressional investigation process for electoral gain against
their political opponents (Kriner and Schickler 2016; Lowande and Peck 2017), and presidents seek to politicize the
bureaucracy for personal gain (Gordon 2011; Lewis 2010).
6 The norm of senatorial courtesy, whereby Senators defer to the judgment of a home-state Senator for nomina-
4
George Washington, John Rutledge’s opposition to the Jay Treaty with Britain cost him support
from Senate Federalists and led to his defeat (Davis 2005). John Adams’ lame-duck appointment of
the “Midnight Judges” to the federal judiciary infuriated Jeffersonian Republicans, who depicted
each of these new judges as a “staunch Federalist” unsympathetic to the goals of the incoming
administration (Carpenter 1915). And John Tyler’s persistent policy clashes with congressional
Whigs spilled over into nomination battles, with Congress either refusing to consider or rejecting eight of Tyler’s nominees to the Court (Beth and Palmer 2009). In all, the Senate rejected
approximately one-third of all Supreme Court nominees in the nineteenth century (Tulis 1997),
a considerably higher rate than in the modern era.
The failed nomination of Robert Bork to the Supreme Court may have marked an intensification of partisan conflict in the nomination process (Cottrill and Peretti 2013; Epstein et al.
2006), which may have reached a fever pitch with the Senate’s refusal to confirm the nomination
of Merrick Garland in 2016. Secular trends in American politics, such as party polarization and
the greater role of the courts in deciding matters of policy, may also contribute to the increased
contentiousness of judicial nominations (Binder and Maltzman 2009). Rhetoric that accompanied
recent nominations to the Supreme Court highlights this partisan contentiousness. Democratic
leaders in the Senate referred to Neil Gorsuch as a “radical” with “right-wing, pro-big business
views” and “not a neutral legal mind but someone with a deep-seated conservative ideology.”7
Similarly, Republican Senator Chuck Grassley depicted Elena Kagan as an individual with “deeply
held liberal principles” who would “use her personal politics and ideology to drive her legal philosophy” on the Court.8
tions to the lower federal courts, may limit the number of starkly partisan fights for appointments to lower courts
(Chase 1972), though the extent of this deference may have overstated in earlier literature (Binder and Maltzman
2004).
7 Senate Democrat quotes are from Elizabeth Warren and Chuck Schumer, respectively, statements
available here: https://www.bostonglobe.com/opinion/2017/03/19/neil-gorsuch-does-not-belong-supreme-court/
elq2QqQBdJW5Fh0s2isXhJ/story.html and here: http://wapo.st/2mXUbTT.
8 Statement available here: https://www.grassley.senate.gov/news/news-releases/senator-grassleys-statementjudiciary-committee-exec-elena-kagan-be-associate.
5
Politicization and the Supreme Court Nomination Process
Despite the centrality of partisan and ideological conflict in Supreme Court nominations,
relatively little scholarship studies how politicization of the judicial nomination process shapes
public attitudes toward specific nominees and the courts more generally. In fact, no study of
which we are aware directly studies how politicization affects how the public evaluates Supreme
Court nominees. Recent research by Sen (Forthcoming), however, provides provocative evidence
that the partisan leanings of judicial nominees are by far the most important factor affecting
public support for them, and further shows that the presence of partisan information reduces the
importance of the nominee’s other qualities such as gender, legal training, and professional experience. Other research in this area emphasizes how the nominee’s legalistic principles (Gibson
and Caldeira 2008) and an individual’s political awareness, partisanship, and policy preferences
(Caldeira and Smith 1996; Gimpel and Wolpert 1996) structure attitudes toward judicial nominees. Much of what we know about politicization and diffuse attitudes toward courts, moreover,
comes from studies of state judicial elections. This research generally finds that elections increase
perceptions of legitimacy by exposing the public to information about the courts and its legitimizing symbols, though politicized campaign advertisements may somewhat attenuate these effects
(Gibson and Caldeira 2009a; Gibson et al. 2011; Gibson 2012). On the other hand, while much of
the public understands the Supreme Court as political and desires that justices are selected based
upon ideological considerations (Bartels and Johnston 2012), other research finds that exposure to
political advertisements in the context of the Alito nomination may have decreased perceptions
of the Supreme Court’s legitimacy (Gibson and Caldeira 2009a)
This previous scholarship on public opinion surrounding judicial nominations is somewhat
limited in scope, however. These studies provide insight into the predictors of support for individual nominees but pay less attention to how rhetoric around the nomination and confirmation
process shapes these attitudes. It is also unclear to what extent the findings from research on
state judicial elections and campaign advertisements generalize to the context of Supreme Court
6
nominations and views of the Court’s legitimacy. Furthermore, no study speaks to the effects of
politicizing the nomination process by politicians in the adjoining branches of government — that
is, the visible statements made by presidents and the hearings held by Senators throughout the
nomination and confirmation process. How, then, might the politicization of the Supreme Court
nomination process by elected officials shape public attitudes toward specific Court nominees
and, more broadly, toward the legitimacy of the Court itself?
Politicization, Elite Signals, and Opinion Polarization
We argue that politicized messages from Senators and the president in relation to Supreme
Court nominees polarizes support for the nominees and the Court across partisan lines. Our theory builds upon foundational work in American politics that notes the importance of partisan
and ideological cues in shaping political evaluations (Campbell et al. 1960; Kuklinski and Quirk
2000). Of critical importance is the role that trusted elite signals play in determining an individual’s opinion on a given issue. We argue that individuals, when exposed to a politicized message
from a prominent elite — for instance, a president or Senator — about a nominee to the Court, use
these messages as cues as to how they should update their attitudes toward the nominee and the
Court as a whole. This, then, will lead individuals of different partisan stripes to diverge in these
evaluations. Partisans who receive positive signals about the nominee from their co-partisans
(and negative signals from opposite partisans) should increase support for the nominee at hand
and the Court more generally, whereas the reverse should occur for individuals who receive negative signals from co-partisan elites (and positive signals from opposite partisans). For example,
suppose a self-identified Republican is exposed to a message from Donald Trump supporting his
nominee’s conservative record or a message from a Senate Democrat characterizing the nominee
in a negative light. These messages serve as cues of the individual’s likely orientation toward the
nominee and, in this case, should lead the individual to increase his support for the nominee and
the Court as a whole.
7
Our expectations receive support from related literature on public responses to elite signals.
Studies of “going public” highlight the presidents’ ability to generate support for their policy
programs, particularly when the president is popular and serves as a trusted elite (Canes-Wrone
2006; Kernell 1993). Elite rhetoric shapes public opinion across a range of policy domains (e.g.,
Berinsky 2007; Kriner and Reeves 2014), often leading to divergence in public opinion across
partisans toward the relevant policy. Additionally, despite long-standing evidence of stability in
aggregate judicial legitimacy, recent studies (Bartels and Johnston 2013; Christenson and Glick
2015) indicate that dissatisfaction on partisan or ideological grounds with Court rulings can reduce individuals’ perceptions of legitimacy (c.f. Gibson, Caldeira, and Spence 2003; Gibson and
Nelson 2015). Taken together, these studies suggest that politicized judicial nominations increase
the salience of partisan and ideological considerations for evaluating the nominee and the Court
more generally, thus generating divergent attitudes across partisan lines.9
Our expectation that politicized rhetoric about judicial nominees leads to polarized public
attitudes contrasts with existing theories that predict either uniformly negative or minimal shifts
in these attitudes after exposure to politicized nominations. For instance, Gibson et al. (2011)
provide evidence that the uniquely high levels of legitimacy of the judiciary are due to the fact
that the public views judges as different than “ordinary politicians.” To the degree to which the
politicization of the nomination process drives the public to view judges in the same light as
they view their elected officials, we may expect that partisan messages from Senators leads to
the diminution of judicial legitimacy. On the other hand, evidence also suggests that the public
expects judges to hold politicized views (Gibson 2012) and even desires a certain degree of politicization in the nomination process (Bartels and Johnston 2012). Then, to the extent to which the
public understands the politicization of the nomination process by legislators and the president
9 However, this expectation contrasts with Gibson (2007), who finds little differences across partisans in their
views toward the Court’s legitimacy and Gibson and Caldeira (2008), who find that, at least in the context of the
Samuel Alito nomination, perceptions of Alito’s legal principles mattered more than partisanship and ideology in
shaping support for his nomination.
8
as a natural extension of how the judicial process works, we may expect little to no reaction to
politicized statements about Court nominees.
Data and Methods
We conducted an experiment embedded in a nationally representative survey to investigate
how the politicization of Supreme Court nominees affects attitudes toward the Court. The survey
was conducted by YouGov with a sample of 2,500 respondents weighted to characteristics of the
national population.10 Table A.1 in the Supplementary Appendix provides descriptive statistics
for the sample.
An experiment is well suited for studying our hypotheses because randomization of the treatment assignment — here, politicized rhetoric related to a Supreme Court nominee — provides a
high level of internal validity for concluding that any potential differences in respondents’ attitudes are due to the treatment and not other potential confounding factors. Two key characteristics of our survey help maximize the external validity of our experimental findings. First, we
fielded the survey in a context where a nomination to the Supreme Court was imminent. Though
Barack Obama nominated Merrick Garland to fill the Supreme Court seat that became vacant
upon the death of Antonin Scalia, the Senate failed to confirm Garland and the seat was left
open when Donald Trump assumed office. Nominating a successor to Scalia was a top priority
for Trump and it was widely expected that the nominee would be announced in the first weeks
of his presidency. Thus, we began fielding our survey on January 21, 2017, the day following
Trump’s inauguration, and interviews were completed on January 30. Somewhat fortuitously,
Trump announced the nomination of Neil Gorsuch the following day, January 31.11 That we
10 YouGov
uses an opt-in internet panel rather than a national probability sample, though recent research shows
that estimates of treatment effects appear similar across sampling frames (Berinsky, Huber, and Lenz 2012). YouGov
respondents were matched to a target sampling frame on gender, age, race, education, party identification, ideology,
and census region.
11 Though Gorsuch’s name had been circulated as a potential Supreme Court nominee as our survey data were
collected, most Americans knew little about him and this is unlikely to have affected their responses. See, e.g., http://
9
asked respondents to evaluate a hypothetical Supreme Court nominee during a period when potential nominees were actively considered lends realism to our study that may be less present in
other surveys in which respondents are asked to consider hypothetical scenarios.
Second, we used a conjoint design to present respondents with a set of attributes that characterized potential Supreme Court nominees. These attributes contained information about the
potential nominee’s gender, race or ethnicity, age, legal training, professional experience, and
ideology, which we discuss below in greater detail. These attributes are commonly invoked by
presidents, Senators, members of the legal community, and political commentators when discussing the merits of Supreme Court nominees. By presenting these attributes to respondents,
we provide a fairly realistic and comprehensive description of the nominee with the kinds of
information the public may draw from when forming their assessments of a nominee.
Our experiment follows the design used in Sen (Forthcoming) in which respondents are presented with information about hypothetical Supreme Court nominees. Respondents were first
told that: “As you may know, the U.S. Supreme Court currently has one vacancy due to the death
of Justice Antonin Scalia in February 2016. President Trump will need to nominate a replacement
justice.” Respondents then received the following prompt: “Suppose Trump is considering nominating the following individual to serve as a justice on the Supreme Court” and were presented
with a series of attributes about the nominee’s biographical information, legal training and experience, and position on abortion. The values of these attributes were randomly assigned to each
respondent and were modeled after realistic characteristics of potential judicial nominees.12
Our key manipulation is the presentation of politicized messages about the potential Supreme
Court nominee. In addition to the six attributes listed above, half of the sample was also ranwww.cbsnews.com/news/americans-sharply-divided-along-partisan-lines-over-travel-ban-trump-cbs-news-poll/.
12 A shortlist of potential Trump nominees for the Supreme Court was prominently floated prior to his inauguration. The backgrounds of the potential nominees varied widely and included several who had not attended elite law
schools or were currently serving as elected politicians — characteristics not typically associated with Supreme
Court picks. See, e.g., http://www.cnn.com/2016/12/06/politics/donald-trump-supreme-court-nominee-shortlist/
(accessed March 26, 2017).
10
domly assigned to receive statements attributed to President Trump and Senate Democrats that
expressed support for and opposition to, respectively, the potential nominee. The statements were
modeled after those made by previous presidents and Senators when discussing characteristics
of recent Supreme Court nominees. Respondents assigned to this condition received statements
from both Trump and Senate Democrats, which simulates the ways political discussions about
judicial nominations occur in the real world in which the public is exposed to competing views
through two-sided information flows. The key independent variable in our primary analysis is
an indicator, Politicized, denoting whether respondents were assigned to receive the statements
attributed to Trump and Senate Democrats. Among the respondents assigned to the Politicized
condition, we further varied the content of the messages from Trump and Senate Democrats so
that they emphasized either the nominee’s qualifications, ideology, personal character, or impartiality. In the analyses that follow we will consider whether the effects of politicization vary with
the specific content of the messages. Table 1 displays the complete list of possible attributes for
the nominees described in the experiment.
After respondents were presented with the profile of a potential Supreme Court nominee, we
asked them to evaluate the nominee and the Court as a whole. We measured respondents’ evaluations of the nominee with a five-point Likert scale in response to the following question: “On a
scale from strongly oppose to strongly support, where would you place your level of support for
this potential nominee?” We then asked respondents to suppose that the nominee was confirmed
by the Senate and began serving as a justice on the Supreme Court. In this context, we measured respondents’ prospective attitudes toward the Supreme Court with a battery of questions
we modeled after a scale commonly used in research on judicial legitimacy. Specifically, we asked
the following:
• If the U.S. Supreme Court started making a lot of decisions that most people disagree with,
it might be better to do away with the Supreme Court altogether.
• I would support removing judges from their position on the U.S. Supreme Court if they
11
Table 1: Characteristics of Potential Supreme Court Nominees
Attributes
Values
Gender
(a) Male; (b) Female
Race
(a) Black; (b) Hispanic or Latina/o; (c) White
Age
(a) 45; (b) 55; (c) 65
Law school attended
(a) Elite law school at an Ivy League university;
(b) Well-regarded law school at a large public university;
(c) Second-tier law school at a regional university;
(d) Law school not ranked in the top 100 law schools
Current position
(a) Federal judge;
(b) Elected politician who has served in office for the last
15 years;
(c) Law professor at a top law school;
(d) Chief counsel at a prominent think tank;
(e) Corporate defense attorney in private practice
Position on abortion
(a) “The Constitution provides fundamental right to privacy and Roe v. Wade is settled law”;
(b) “The Constitution provides fundamental right to privacy but I cannot comment on whether Roe v. Wade was
decided properly”;
(c) “The sanctity of life should be protected and Roe v.
Wade ought to be overturned”
Trump statement of support
(a) “This nominee has an outstanding legal record and is
well-qualified to serve on the Supreme Court”;
(b) “I am proud to nominate a principled conservative who
will honor the legacy of Antonin Scalia”;
(c) “The nominee has the outstanding character Americans expect from a Supreme Court justice”;
(d) “I have known this nominee for many years and believe they will be an excellent Supreme Court justice”
(HALF SAMPLE)
Statement from Senate Democrats
(a) “The nominee does not have the training or the experience worthy of serving on the Supreme Court”;
(HALF SAMPLE)
(b) “The nominee has a troubling ethical record and we
are concerned that they do not meet the standards of the
highest judicial office in the nation”;
(c) “We are not convinced that the nominee will be able to
shed their personal political beliefs and check those biases
at the door of the Supreme Court”;
(d) “We worry that the nominee’s close relationship with
the president would compromise their impartiality”
Attribute values were randomly assigned to respondents for each potential nominee. Subjects
were randomly assigned to receive the statements attributed to Trump and Senate Democrats,
with half of the sample not receiving statements at all and the other half receiving one of the four
statements from Trump and one of the four statements from Senate Democrats shown above.
consistently made decisions at odds with what a majority of the people want.
• The U.S. Supreme Court will have become too independent and should be seriously reigned
in.
• The U.S. Supreme Court will have become too mixed up in politics.
Each question was measured on a five-point scale ranging from “strongly agree” to “strongly disagree.” As in prior research, these questions scale well together (Cronbach’s α = 0.78) and we
used responses to them to measure respondents’ perceptions of judicial legitimacy. Table 2 displays summary statistics for the measures that comprise our dependent variables. Each question
was measured on a five-point scale ranging from “strongly agree” to “strongly disagree.” As in
prior research, these questions scale well together (Cronbach’s α = 0.78) and we used responses
to them to measure respondents’ perceptions of judicial legitimacy.
Each respondent received four profiles of potential Supreme Court nominees, with the dependent variables measured after each of them. Respondents therefore evaluated a total of 10,000
nominee profiles. We evaluate the effect of politicization by regressing the dependent variables
described above on Politicized, the indicator for receiving the messages attributed to Trump and
Senate Democrats, as well as a set of indicators for the other attributes of the potential nominee.
This provides estimates of the Average Marginal Component-specific Effect (AMCE) of each characteristic (Hainmueller and Hopkins 2015). We estimate linear regressions with standard errors
clustered on respondents to account for the non-independence across observations that results
from each respondent being shown multiple profiles.
We test two primary hypotheses using these data. First, in the aggregate we examine the relationship between exposure to politicized messages about the nominee and respondents’ support
for the nominee and perceptions of judicial legitimacy. As we outlined above, existing literature
provides conflicting expectations about the nature of these relationships. Second, we study how
respondents’ political views condition the effect of politicization, focusing specifically on the possibility of heterogeneous treatment effects among respondents with different partisan affiliations.
13
Table 2: Dependent variables: Summary statistics
Support nominee
Strongly
oppose
Somewhat
oppose
Strongly
support
NA
.173
.194
.324
.217
.083
.010
Strongly
disagree
Disagree
Neither agree
nor disagree
Agree
Strongly
agree
NA
If the U.S. Supreme Court
started making a lot of decisions that most people disagree with, it might be better
to do away with the Supreme
Court altogether.
.044
.145
.285
.236
.288
.002
I would support removing
judges from their position on
the U.S. Supreme Court if
they consistently made decisions at odds with what a majority of the people want.
.119
.228
.316
.191
.129
.017
The U.S. Supreme Court will
have become too independent and should be seriously
reigned in.
.052
.176
.406
.216
.110
.040
The U.S. Supreme Court will
have become too mixed up in
politics.
.095
.300
.406
.131
.044
.024
On a scale from strongly
oppose to strongly support,
where would you place your
level of support for this potential nominee?
Neither support Somewhat
nor oppose
support
Legitimacy
Cell entries indicate sample proportions for each variable. N = 10,000.
Results
We begin by considering the aggregate effect of politicization on attitudes toward the nominee
and the court. Figure 1 shows the AMCEs for each attribute of the nominee. For each characteristic, the plotted points show the increase or decrease in support and perceptions of legitimacy,
respectively, relative to the baseline condition. The baseline condition is the first value listed
14
under each attribute category. The horizontal lines are the 95% confidence intervals associated
with the estimates and the vertical dashed line at zero represents the null hypothesis of no effect.
All of our statistical tests are two-sided.
In the aggregate, we find no evidence that politicization affected either respondents’ support
for the nominee or perceptions of judicial legitimacy. As the left plot in Figure 1 shows, support
for the nominee was .044 higher (on a five-point scale) among respondents who received the
quotations attributed to Trump and Senate Democrats, but this estimate is not distinguishable
from zero at conventional levels. The plot on the right side of figure shows that perceptions
of legitimacy were .026 lower (also on a five-point scale) among respondents in the politicized
condition, but this estimate also fails to reach statistical significance. On the whole, therefore, our
data provide no evidence that the politicization of Supreme Court nominations has statistically
or substantively meaningful effects on attitudes toward the nominee or the court more generally.
The results for the other attributes of the nominee are also of substantive interest. The findings, however, are overwhelmingly null. The only exceptions concern the nominee’s abortion
views. Relative to a nominee who believes that Roe v. Wade is settled law and thus does not wish
to implement new restrictions on abortion access, nominees who refused to comment on their
views on Roe or who expressed a desire to overturn the Roe decision received significantly less
support. Given recent trends in Supreme Court nominees’ reticence to express their views on
legal matters related to the more salient policy issues of the day, our results provide some preliminary evidence that — at least on some issues — ambiguity may come at a cost. It is also possible,
however, the respondents inferred that a Trump nominee would be likely to oppose abortion
rights and interpreted the nominee’s refusal to answer the question as an indication that they
were attempting to hide views that are largely unpopular according to recent public opinion
data.13 Across both dependent variables, however, we find no evidence that the nominee’s age,
13 A Pew report issued in January 2017 finds that 69% of Americans oppose overturning Roe; see http://
www.pewresearch.org/fact-tank/2017/01/03/about-seven-in-ten-americans-oppose-overturning-roe-v-wade/ (accessed March 27, 2017).
15
gender, race, professional background, legal training, or professional experience affected respondents’ evaluations.
Figure 1: The Effect of Politicization on Support for Court Nominees and Perceptions of Judicial
Legitimacy
Support nominee
Politicized:
No
Yes
Age:
45
55
65
Gender:
Male
Female
Race:
White
Black
Hispanic or Latino/a
Law School:
Elite Ivy
Well−regarded public
Second tier
Non−top 100
Current Position:
Federal Judge
Elected politician
Law professor
Chief counsel
Corporate attorney
Abortion View:
Roe settled law
Cannot comment
Overturn Roe
Legitimacy
Politicized:
No
Yes
Age:
45
55
65
Gender:
Male
Female
Race:
White
Black
Hispanic or Latino/a
Law School:
Elite Ivy
Well−regarded public
Second tier
Non−top 100
Current Position:
Federal Judge
Elected politician
Law professor
Chief counsel
Corporate attorney
Abortion View:
Roe settled law
Cannot comment
Overturn Roe
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
−0.2
0.0
0.2
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
−0.2
Estimated effect
0.0
Estimated effect
Note: Plots show the average marginal component effects (AMCEs) of each profile characteristic. The plotted points
are the AMCE estimates and the horizontal lines are the 95% confidence intervals. The AMCEs are estimated relative
to the baseline values of each attribute. The left panel shows results for respondents’ level of support for the nominee
and the right panel shows results for perceptions of judicial legitimacy.
The aggregate results from our conjoint experiment provide two novel findings that contrast
with accounts that link politicization and public opinion toward the courts. Political rhetoric
from presidents and the opposition party in the Senate does not appear to systematically damage
a Supreme Court nominee’s standing with the public. Moreover, and contrary to concerns raised
by scholars, political observers, and justices themselves, we find no evidence that politicization
of Supreme Court nominations affects perceptions of the court’s legitimacy. We now investigate
our hypothesis that the effects of politicization vary with respondents’ partisanship.
16
0.2
How Partisanship Conditions the Effect of Politicization
Our theoretical argument predicts that politicization has divergent effects on Democrats and
Republicans. In the context of a Republican presidency, we expect that politicized rhetoric leads
to more positive evaluations from Republicans and more negative evaluations among Democrats.
To test our hypothesis, we estimated models similar to those reported above but interacted assignment to the Politicized condition with party identification. We distinguished respondents’
partisanship based on whether they self-identified as Democrats, Republicans, or Independents.
Approximately a third (34.4%) of the sample identified as Democrats, 26.0% identified as Republicans, and 29.9% identified as Independents. Another 4.5% indicated their party affiliation as
“Other” and 5.3% reported they were unsure of their partisanship. For simplicity, we combined
Independents with respondents who identified with these latter two categories, but we note our
results are substantively identical when excluding individuals who do not identify with either of
the two major parties or as Independents. In addition, we obtained identical patterns of results
when classifying “leaners” as partisans rather than as Independents.14
Figure 2 reports the average component interaction effect (ACIE) of politicization by political
party. The effects on respondents’ support for the nominee are shown with triangles and perceptions of legitimacy are shown with circles. The vertical lines show the 95% confidence intervals
associated with the estimated effects and the dashed horizontal line at zero indicates the null
hypothesis of no effect from politicization.
The results in Figure 2 provide strong support for our hypothesis. Among Democrats, politicization significantly reduced support for the nominee (-0.29) but significantly increased support
for the nominee among Republicans (0.34). These effects are statistically distinguishable at p <
.001. Politicization appeared to have had no impact on nominee support among Independents,
however, as the estimated effect is much smaller in magnitude (.08) and not statistically distinguishable from zero at conventional levels.
14 Please
see Figure A.1 in the Supplementary Appendix.
17
We find similar patterns when examining respondents’ perceptions of judicial legitimacy.
While politicization significantly decreased judicial legitimacy among Democrats (-0.16), it increased legitimacy among Republicans (0.09), though the latter estimate falls short of statistical significance (p = .21). However, the estimates are statistically different from one another (p
< .02), indicating that politicization had a differential effect on legitimacy for Republicans and
Democrats. We again find that politicization had no effect on perceptions of legitimacy among
Independents, as the observed effect is extremely close to zero (-0.01).
Figure 2: Politicization, Partisanship, and Attitudes toward the Court
0.6
● Support nominee
●
●
Perceptions of legitimacy
●
Estimated effect
0.3
●
●
●
●
●
0.0
●
●
−0.3
●
Democrats
Independents
Republicans
Note: The plot shows the average marginal interaction effect of politicization for respondents who identify as
Democrats, Independents, and Republicans, as indicated along the x-axis. Results for respondents’ support for the
nominee are shown with an orange triangle (N) and results for perceptions of judicial legitimacy are shown with a
blue circle ( ). The vertical lines indicate the 95% confidence intervals associated with the effects. Positive values
along the y-axis indicate increased support and legitimacy while negative values indicate decreased support and
legitimacy. The dashed horizontal line at zero shows the null hypothesis of no effect.
Consistent with our expectations, partisans responded to politicized messages about Supreme
Court nominees in predictably partisan ways. The president’s copartisans were more supportive
18
of the nominee when the nominee was endorsed by the president and criticized by the opposition
party in the Senate. Respondents who were members of the party opposite the president, however,
reduced their support of the nominee when exposed to the same messages. In both cases, the
evidence suggests that partisans respond to the information from elite sources and adjusted their
evaluations of the nominee accordingly. Moreover, it appears that the effects from the politicized
rhetoric that accompanied the Supreme Court nominees in our study spilled over to respondents’
evaluations of the Court more generally. Politicization of the nominee increased the Court’s
legitimacy among the president’s copartisans but reduced it among members of the opposite
party. The largely null findings in the aggregate, therefore, disguised divergent effects among
partisans. Altogether, our results indicate that the politicization of judicial nominees can polarize
partisans’ opinions toward the court.
Republicans and Democrats do not inherently approve and disapprove of politicization, respectively. Instead, our findings reflect respondents’ partisan alignment with the president and
the opposition party. Consistent with this, we find similar results when distinguishing respondents based on their favorability toward President Trump rather than by partisanship.15 Among
respondents with favorable attitudes toward Trump (41.3% of the sample), politicization significantly increased support for the nominee (0.43); however, politicization significantly decreased
support for the nominee among respondents with unfavorable attitudes toward Trump (-0.22).
Each of these effects is statistically distinguishable from zero; they are also statistically distinguishable from each other. Similarly, politicization increased legitimacy among respondents with
favorable attitudes toward Trump (.09) but reduced it among respondents with unfavorable attitudes toward Trump (-.10), though both of these estimates fall short of conventional levels of
statistical significance (p = .141 and .053, respectively). The effects are statistically distinguishable from each other, however, providing evidence that attitudes toward Trump generated quite
different reactions to politicization.
15 These
results are shown in Figure A.2.
19
It is worth emphasizing, however, that our results do not simply reflect divergent responses to
invoking the nominating president in the treatment condition.16 Skeptical readers may wonder,
for instance, whether respondents in the treatment condition were reacting to the use of Trump’s
name rather than the quotation in support of the nominee. Recall, however, that as we described
above, all respondents in our study received a prompt that referenced President Trump’s role in
filling the Supreme Court vacancy left open by the death of Antonin Scalia. This prompt appeared
at the same time that respondents received the information about the characteristics of the potential nominee. While it is possible that partisans in the control group were more polarized over
the nominee than they otherwise might had been if Trump were not referenced in the opening
prompt, it is clear that the quotations attributed to Trump and Senate Democrats significantly
exacerbated these partisan differences. The treatment effects we identify are thus attributable to
the president’s (and the partisan opposition’s) political rhetoric toward the nominee rather than
the fact of presidential involvement in the nominating process.
Robustness Checks and Extensions
We conducted several robustness checks to further study the relationship between politicization, partisanship, and evaluations of the nominee and the court. First, though somewhat less
connected with our theory, we explored potential interactions between partisanship and politicization with the other attributes of the judicial nominees in our study. For the most part, interestingly, we find little evidence that partisanship conditioned the effects of the other characteristics
of the nominee.17 Differences in the nominee’s age, gender, race, legal training, and current position all had similar effects among Republicans, Democrats, and Independents alike. The chief
exception concerned, perhaps unsurprisingly, the nominee’s view on abortion. Nominees who
wished to overturn Roe received significantly less support among Democrats and Independents
16 For
instance, presidential involvement can polarize legislators’ responses to issues important to the president
(see, e.g., Lee 2008).
17 Please see Figure A.3 in the Supplementary Appendix.
20
yet significantly greater support from Republicans.
Second, we also find limited evidence that politicization conditioned the effects of the other
characteristics of the nominee.18 We do find that politicization significantly decreased support for
female nominees (relative to male nominees), but we do not find similar effects for the legitimacy
dependent variable. None of the other characteristics vary systematically with the presence of
politicization. The absence of a conditional relationship between politicization and the other
characteristics could indicate that political messages from partisan actors increase the salience of
partisanship for evaluating judicial nominees but do not influence how the public considers their
other attributes.
Third, our argument predicted that praise and criticism directed at Supreme Court nominees
would polarize public opinion toward the nominee and the Court. Though our account focuses
primarily on the political actors who send messages in reference to a judicial nominee, it is also
possible that the content of the messages generates varying responses from the public. We investigated this possibility by examining the effects of each of the different messages attributed
to President Trump and Senate Democrats and described in Table 1. Some of these messages
emphasized, for instance, the nominee’s political views while others emphasized the nominee’s
qualifications or relationship with the president. If politicization affects public opinion by making
salient the ideological characteristics of the nominee, we might expect to find the largest effects
from messages that emphasized the nominee’s personal views. On the other hand, politicization
could affect public opinion based on the sender’s attributes, in which case the contents of the
messages could matter less than the political alignment between the sender and members of the
public.
Generally speaking, we do not find that the effects varied based on the specific content of the
messages.19 Compared to respondents who were not in the politicized condition, we find that all
18 Please
19 The
see Figure A.4 in the Supplementary Appendix.
results are shown in Figure A.5 in the Supplementary Appendix.
21
variants of the messages consistently reduced evaluations of the nominee and the Court among
Democrats but increased evaluations among Republicans. Not all the estimates are statistically
distinguishable from zero, likely due to the reduced sample sizes who received each of the specific
messages, yet the effects estimates are also not distinguishable from each other within partisans.
Perhaps most importantly, criticism or praise that references the nominee’s ideological beliefs did
not result in substantially more polarized reactions from partisans than messages that emphasized
the nominee’s character or qualifications. The findings suggest that the effects we uncover as a
result of politicization reflects the identity of the political actors from whom the messages are
sent rather than the nature of the comments themselves.
Finally, we explored whether the effect of politicization was conditioned by other attributes
of respondents that previous research has identified as important contributors to public opinion
toward courts. First, we investigated whether politicization was conditioned by knowledge about
the Court. We measured knowledge with a five-item battery that included items recommended
by Gibson and Caldeira (2009b) and used in Sen (Forthcoming).20 We created an indicator to distinguish respondents who correctly answered either four or five items (38.2% of the sample) from
those who provided fewer correct answers. We then estimated the average component interaction effect between judicial knowledge and politicization. We found some suggestive evidence
of an interaction effect. The effect of politicization on both support and legitimacy was negative among people with low knowledge yet positive among respondents with higher knowledge.
While none of the estimates were statistically distinguish from zero, the estimates were statisti20 The
five questions were asked prior to the treatment assignment and were worded as follows: (1) “Some judges
in the U.S. are elected; others are appointed to the bench. Do you happen to know if the Justices of the U.S. Supreme
Court are elected or appointed to the bench?”; (2) “Some judges in the U.S. serve for a set number of years; others
serve a life term. Do you happen to know whether the Justices of the U.S. Supreme Court serve for a set number of
years or whether they serve a life term?”; (3) “Do you happen to know who has the last say when there is a conflict
over the meaning of the U.S. Constitution—the U.S. Supreme Court, the U.S. Congress, or the President?”; (4) Please
select the name of the current Chief Justice of the United States from the choices below: a. William Rehnquist, b.
Stephen Breyer, c. Antonin Scalia, d. John Roberts, e. Anthony Kennedy; (5) Please select the name of the Justice
who most recently joined the U.S. Supreme Court from the choices below: a. Samuel Alito, b. Elena Kagan, c. Sonia
Sotomayor, d. John Roberts, e. Sandra Day O’Connor. Accuracy rates ranged from 22.5% (item 5) to 76.4% (item 1).
22
cally distinguishable from each other (p = .034) for the legitimacy variable and were statistically
distinguishable at p = .107 for the support variable. We are reluctant to overinterpret these results given their fragility, but they do provide preliminary evidence that politicization has a more
positive effect among members of the public who are better versed in the details of the Court
(see, e.g., Gibson and Caldeira 2009b; Gibson and Nelson 2014).
We found less evidence, however, that the effect of politicization was conditioned by respondents’ favorability toward the Court, their attentiveness to news and information about the Scalia
vacancy, or the degree of importance they assigned to the identity of the individual nominated to
Supreme Court. In each case, we created indicators to distinguish respondents who viewed the
Court favorably, who had heard “a lot” about the vacancy that resulted from Scalia’s death, and
for whom the choice of the next justice was “very important” personally for the respondent.21
Across each variable, the effects of politicization are not statistically distinguishable from zero
for any subgroup and are indistinguishable from each other.
Conclusion
Contemporary battles over Supreme Court nominees are unavoidably, and perhaps inevitably,
political. When a Supreme Court vacancy arises, presidents make public speeches to introduce
and rally the country behind their nominee. Senators, particularly members of Judiciary Committee, frequently appear before the media to praise or criticize the nominee’s qualifications, record,
or character. The political drama that accompanied the failed nomination of Robert Bork, the
hotly debated nomination of Clarence Thomas, and the Senate’s failure to consider the nomination of Merrick Garland has generated concern from all sides of the political spectrum about
the deleterious consequences of politicization. Not only may politicized nomination processes
21 Each of these questions was administered before the treatment was assigned.
61.1% of respondents held favorable
views toward the Supreme Court, 38.0% had heard “a lot” about Scalia’s death and the resulting vacancy, and 52.8%
of respondents said the choice of the replacement justice was “very important” to them.
23
elevate political factors over legal qualifications and threaten the viability of well-credentialed
jurists (e.g., Epstein et al. 2006), they may also inflict institutional harm by weakening judicial
legitimacy. Motivated by such concerns as these, appointments to high courts in Europe are now
performed by independent committees (as in Denmark, Norway, and the United Kingdom) or
require confirmation by overwhelming supermajorities so as to require broad consensus across
parties (as in Germany).
We contribute new evidence about how the politicization of U.S. Supreme Court nominations
affects public opinion. In the aggregate, we find little support for claims that politicized nominations reduce public support for the nominee or reduce evaluations of judicial legitimacy. Based on
our findings, nominees and courts themselves appear largely inoculated from reductions in aggregate public support when the nomination is politicized. Our data further reveal deep partisan
divisions, however, in how the American public responds to politicization. When a nomination is
politicized, the president’s copartisans increase their evaluations of the nominee while members
of the opposite party reduce their support. Further, and perhaps more damagingly, we find that
the effects of politicization extend to more general evaluations of the Court’s legitimacy. While
politicization leads the president’s copartisans to see the Court in a more favorable light, it reduces the Court’s standing among members of the opposite party. Our findings thus provide some
support for concerns expressed by Chief Justice John Roberts, who argued that “[w]hen you have
a sharply political, divisive hearing process, it increases the danger that whoever comes out of it
will be viewed in those terms. . . If the Democrats and Republicans have been fighting so fiercely
about whether you’re going to be confirmed, it’s natural for some members of the public to think,
well, you must be identified in a particular way as a result of that process.” The results also suggest that politicized nomination procedures may weaken the Court’s legitimacy by sowing public
distrust in governing institutions.22
22 See, e.g., “The Unfortunate Politicization of Judicial Confirmation Hearings”, John G. Walker, Jr., Jul 9, 2012,
The Atlantic; available at https://www.theatlantic.com/national/archive/2012/07/the-unfortunate-politicization-ofjudicial-confirmation-hearings/259445/ (accessed March 30, 2017).
24
Our findings have several important implications for research on the judiciary and political institutions more generally. First, our study complements recent literature that investigates
whether support for the Court is contingent upon satisfaction with its rulings (Bartels and Johnston 2013; Christenson and Glick 2015; Gibson and Nelson 2015). While this body of research
focuses on how public opinion responds to judicial outputs, our study indicates that public opinion is responsive to the procedural factors that determine the composition of the Supreme Court.
These findings build on recent research in the context of other political institutions that shows
the public responds to the ways public policies are fashioned in addition to the policy outcomes
themselves (e.g., Christenson and Kriner Forthcoming; Reeves and Rogowski Forthcoming). Second, our results highlight the fundamental interdependence of American political institutions.
Courts are not immune to political discourse that originates from actors in other branches of
government and, as we show, the public is not immune to responding to these messages in predictably political wars. While the Supreme Court may be deeply concerned with maintaining
its legitimacy, our findings suggest that political incentives for members of other branches of
government pose an obstacle for the Court to do so. Third, our results have implications for a
president’s calculation about when and whether to “go public” in support of a Supreme Court
nominee. Supreme Court nominations appear to be an exemplar case of what Cameron and Park
(2011) call “opinion contest theory” and thus a president’s decision to speak out on behalf of a
nominee may depend on the relative mobilization of his copartisans and members of the opposite
party. Finally, our findings provide some evidence that the polarized partisan reaction to recent
Supreme Court nominees documented by Kastellec, Lax, and Phillips (2010) may in part reflect
the increased politicization of judicial nominations in the last several decades.
We close with some unresolved questions and opportunities for future research. Our findings
related to the Court’s legitimacy raise important normative and empirical questions about the
concept of legitimacy. It is somewhat unclear to us, for instance, whether our findings related to
partisanship and legitimacy ought to raise concern. On the one hand, aggregate levels of legiti25
macy did not change when the nominee in our experiment was politicized. On the other hand, is
institutional legitimacy threatened when citizens of different partisan stripes regard the Court in
vastly different ways? As the Court relies upon legitimacy to secure voluntary compliance with
its decisions (Gibson 2015), the fact that contentious nominations appear to degenerate support
among opposite partisans — the individuals in society most likely to disagree with a new nominee’s rulings — may bode poorly for the institutional power of the judiciary. We hope our findings
will prompt discussion about the conception of legitimacy and its manifestations in public opinion. Second, our study leaves open the question of whether the effects we identify will persist
over time and if they do, to what degree. We suspect that the impact of politicization nominations on views toward the Court may be relatively fleeting as public attentiveness subsides once
a nominee has been confirmed. But it is also possible that successive intensely politicized nominations could have a deeper and more cumulative effect on public opinion. This is an important
question for further research. Finally, we note that the limits of experimentation apply to our
study. Though we conducted our experiment in a context designed to maximize external validity, additional research is needed to probe the generalizability of our findings both in the United
States and in settings with different institutional contexts.
26
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A
Supplementary Appendix
Table A.1: Descriptive Statistics
Category
Proportion
Gender
Male
Female
.482
.518
Race
White
Black
Latina/o
Asian American
Other racial group
.676
.116
.138
.027
.044
Partisanship
Democrat
Republican
Independent
Other
Not sure
.328
.251
.323
.018
.080
Category
Proportion
Education
No high school degree
High school graduate
Some college
Two-year degree
Four-year degree
Postgraduate degree
.120
.312
.215
.097
.165
.091
Income
Under $20,000
$20,000 to $39,999
$40,000 to $59,999
$60,000 to $79,999
$80,000 to $99,999
$100,000 to $149,999
$150,000 or more
Prefer not to say
.220
.221
.156
.097
.061
.071
.033
.142
Ideology
Very liberal
.060
Liberal
.194
Moderate
.337
Conservative
.270
Very conservative
.048
Not sure
.090
Cell entries indicate sample proportions for each demographic and political
category. N = 2,500.
32
Figure A.1: The Effect of Politicization on Support for Court Nominees and Perceptions of Judicial Legitimacy
(a) Excluding respondents who do not identify as
Democrats, Republicans, or Independents
(b) Classifying “leaners” as partisans
0.6
● Support nominee
● Support nominee
●
●
●
●
Perceptions of legitimacy
●
●
0.3
●
●
●
● ●
Estimated effect
Estimated effect
0.3
0.0
●
●
●
●
●
●
Democrats
●
●
0.0
●
●
−0.3
Perceptions of legitimacy
−0.3
Independents
Republicans
●
Democrats
Independents
Republicans
Note: Plots show the average marginal interaction effect of politicization for respondents who identify as Democrats,
Independents, and Republicans, as indicated along the x-axis. Results for respondents’ support for the nominee are
shown with an orange triangle (N) and results for perceptions of judicial legitimacy are shown with a blue circle
( ). The vertical lines indicate the 95% confidence intervals associated with the effects. Positive values along the
y-axis indicate increased support and legitimacy while negative values indicate decreased support and legitimacy.
The dashed horizontal line at zero shows the null hypothesis of no effect.
Figure A.2: Attitudes toward President Trump and the Effect of Politicization
0.6
● Support nominee
●
●
Perceptions of legitimacy
●
Estimated effect
0.4
0.2
●
●
0.0
●
●
−0.2
●
−0.4
Favorable
Unfavorable
Note: The plot shows the average marginal interaction effect of politicization for respondents with favorable and
unfavorable attitudes toward President Trump, as indicated along the x-axis. Results for respondents’ support for
the nominee are shown with an orange triangle (N) and results for perceptions of judicial legitimacy are shown with
a blue circle ( ). The vertical lines indicate the 95% confidence intervals associated with the effects. Positive values
along the y-axis indicate increased support and legitimacy while negative values indicate decreased support and
legitimacy. The dashed horizontal line at zero shows the null hypothesis of no effect.
34
Figure A.3: Partisanship and Support for Court Nominees and Perceptions of Judicial Legitimacy
(a) Support for the nominee
Conditional on
Party = Democrat
Politicized:
No
Yes
Age:
45
55
65
Gender:
Male
Female
Race:
White
Black
Hispanic or Latino/a
Law School:
Elite Ivy
Well−regarded public
Second tier
Non−top 100
Current Position:
Federal Judge
Elected politician
Law professor
Chief counsel
Corporate attorney
Abortion View:
Roe settled law
Cannot comment
Overturn Roe
Conditional on
Party = Independent
●
Conditional on
Party = Republican
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
−0.50 −0.25 0.00
0.25
●
●
0.50 −0.50 −0.25 0.00
0.25
0.50 −0.50 −0.25 0.00
0.25
0.50
Estimated effect
(b) Perceptions of legitimacy
Conditional on
Party = Democrat
Politicized:
No
Yes
Age:
45
55
65
Gender:
Male
Female
Race:
White
Black
Hispanic or Latino/a
Law School:
Elite Ivy
Well−regarded public
Second tier
Non−top 100
Current Position:
Federal Judge
Elected politician
Law professor
Chief counsel
Corporate attorney
Abortion View:
Roe settled law
Cannot comment
Overturn Roe
Conditional on
Party = Independent
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
−0.2
Conditional on
Party = Republican
●
●
0.0
0.2
−0.2
●
0.0
0.2
−0.2
0.0
0.2
Estimated effect
Note: Plots show the average marginal component effects (AMCEs) of each profile characteristic by respondent
partisanship. The top panel shows results for respondents’ level of support for the nominee and the bottom panel
shows results for perceptions of judicial legitimacy.
Figure A.4: Politicization and Support for Court Nominees and Perceptions of Judicial Legitimacy
(a) Support for the nominee
Conditional on
Politicized = 0
Age:
45
55
65
Gender:
Male
Female
Race:
White
Black
Hispanic or Latino/a
Law School:
Elite Ivy
Well−regarded public
Second tier
Non−top 100
Current Position:
Federal Judge
Elected politician
Law professor
Chief counsel
Corporate attorney
Abortion View:
Roe settled law
Cannot comment
Overturn Roe
Conditional on
Politicized = 1
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
−0.50
●
−0.25
0.00
0.25
0.50
−0.50
−0.25
0.00
0.25
0.50
Estimated effect
(b) Perceptions of legitimacy
Conditional on
Politicized = 0
Age:
45
55
65
Gender:
Male
Female
Race:
White
Black
Hispanic or Latino/a
Law School:
Elite Ivy
Well−regarded public
Second tier
Non−top 100
Current Position:
Federal Judge
Elected politician
Law professor
Chief counsel
Corporate attorney
Abortion View:
Roe settled law
Cannot comment
Overturn Roe
Conditional on
Politicized = 1
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
−0.2
●
0.0
36 0.2
−0.2
0.0
0.2
Estimated effect
Note: Plots show the average marginal component effects (AMCEs) of each profile characteristic based on whether
respondents were assigned to receive politicized messages about the nominee. The top panel shows results for respondents’ level of support for the nominee and the bottom panel shows results for perceptions of judicial legitimacy.
37
Estimated effect
−0.4
0.0
0.4
−0.8
−0.4
0.0
0.4
0.8
●
●
●
●
●
●
●
●
●
●
Experience
●
●
●
●
●
●
●
●
● Independence
Character ●
Beliefs
Support nominee
●
●
●
●
Democrats
● Experience
●
Personal
●
Character ●
relationship
Beliefs
Support nominee
●
●
●
●
Democrats
−0.8
−0.4
Support nominee
●
●
●
●
●●
●
●
●
●
●
●
Perceptions of
legitimacy
●
●
●
●● ●
● ●
● Experience
●
Personal
●
Character ●
relationship
Beliefs
Independents
−0.8
−0.4
0.0
0.4
0.8
Perceptions of
legitimacy
●
●
●●
●
●
●
●
−0.4
0.0
0.4
●
●
Experience
●
●
● ●
● ●●
●
● Independence
Character ●
Beliefs
Support nominee
●
●
●
●
Independents
Perceptions of
legitimacy
●
●
●
●
●
● ●
●
−0.4
0.0
0.4
(b) Effects of Politicized Messages from Senate Opposition
Perceptions of
legitimacy
●
●
●
●
●●
●
●
0.0
0.4
0.8
(a) Effects of Politicized Messages from the President
●
●
Support nominee
●
●
●
●
●
●
Support nominee
●
●
●
●
●
●
●
●
●
●
●
●
Experience
Perceptions of
legitimacy
●
●
●
●
●
●
●
●
● Independence
Character ●
●
●
Perceptions of
legitimacy
●
●●
●
●
●
●
●
● Experience
●
Personal
●
Character ●
relationship
Beliefs
Beliefs
Republicans
●
●
●
●
Republicans
Figure A.5: Message Content and the Effect of Politicization across Partisans
Estimated effect
Estimated effect
Note: Plots show the average marginal interaction effect of different messages related to politicization for respondents who identify as Democrats,
Independents, and Republicans, as indicated along the x-axis. The content of the messages is distinguished with the various colors of the filled circles.
The vertical lines indicate the 95% confidence intervals associated with the effects. Positive values along the y-axis indicate increased support and
legitimacy while negative values indicate decreased support and legitimacy. The dashed horizontal line at zero shows the null hypothesis of no effect.
Estimated effect
Estimated effect
Estimated effect