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Supreme Court Decision Making, Case Salience, and the Attitudinal Model
Isaac Unah
Associate Professor
Department of Political Science
University of North Carolina
Chapel Hill NC 27599-3265
[email protected]
Ange-Marie Hancock
Department of Political Science
Yale University
New Haven, CT 06520-8209
[email protected]
Send all inquiries related to this paper to the first author. We would like to thank Larry Baum, Jeffrey Segal,
Marco Steenbergen, Chris Zorn and five anonymous reviewers of Law and Policy for their constructive
comments. An earlier version of this paper was presented at the annual meeting of the American Political
Science Association, Chicago IL, 2000. The University of North Carolina-Chapel Hill Research Council
provided some funding that supported this research.
Bibliography
Isaac Unah is Associate Professor of Political Science. His primary area of research interest is judicial politics
and its influence on public policy. He is currently researching the role of politics and culture in the
implementation of capital punishment in the United States.
Ange-Marie Hancock is Assistant Professor of Political Science and African American Studies. She received
her Ph.D. from the University of North Carolina at Chapel Hill in 2000. Her research interests stand at the
crossroads of American politics and political theory.
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U.S. Supreme Court Decision Making, Case Salience, and the Attitudinal Model
ABSTRACT
Does case salience condition the role of ideological preferences in the decisions of U.S. Supreme Court
justices? Does the attitudinal model of judicial behavior hold equally true in high salience and low salience
cases? In this paper, we analyze the role of case salience as a moderating influence on the explanatory capacity
of the attitudinal model and test the strength of the model in high versus low salience contexts. Using civil rights
votes during 47 Supreme Court terms, from 1953 through 2000, we find that although the attitudinal model
explains a substantial proportion of Supreme Court outcomes, the model is sensitive to case salience and that
justices rely significantly more on ideological preferences when deciding high salience cases than low salience
ones. Our findings represent an important qualification to the attitudinal model.
3
I.
INTRODUCTION
Empirical studies of judicial behavior in the U.S. Supreme Court have established credible evidence that policy
disagreements among justices and decision making fall along ideological lines (Schubert 1965; Segal and Spaeth
1993). The proliferation of nonconsensual decisions in recent Court eras is a stark reminder that these
ideological lines have hardened in light of growing public awareness and visibility of Supreme Court decisions
(Walker, Epstein and Dixon 1988; Gerber and Park 1997; Distlear and Baum 2001). This seemingly entrenched
ideological divide may well have implications for the nature of what transpires behind closed doors in the Court
and, more importantly, on how scholars attempt to explain it. Various theories have been proffered to account
for judicial behavior in the Supreme Court. In this paper, we focus on the most popular of those theories in
political science, the attitudinal model, to examine whether case salience conditions the ability of the attitudinal
model to explain Supreme Court decisions.
This is an important theoretical issue for political scientists and sociolegal scholars. If indeed salience of
the case matters significantly in Supreme Court decision making, this may well explain the astonishingly low
impact of legal precedent on judicial voting reported by various studies of Supreme Court behavior. For
example, in their analysis of 346 major cases to assess the influence of stare decisis since the start of the Warren
Court, Segal and Spaeth (1996) found that “90.8% of the votes conform to the justices’ revealed preferences.
That is, only 9.2% of the time did a justice switch to the position established in the landmark precedent” (p.
983). While the attitudinal model has received strong empirical support, we have only recently begun to analyze
whether the model holds equally true in high salience and low salience cases. If it does not, then this calls for an
important qualification to the attitudinal model.
Spaeth and Segal (1999, 309) have presented the first, albeit unsystematic, treatment of this issue. They
used simple cross tabulation of landmark versus ordinary cases to analyze the possibility that case salience
underlies the low impact of precedent on justices’ votes. Spaeth and Segal reported a substantially higher
impact of legal precedent on the least salient of the Court’s cases. What that implies is that if precedent matters
more in low salience cases, then we can, at the very least, assume that judicial preferences would matter less in
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low salience cases and more in high salience ones. A centerpiece of our research here is to test that assumption
by analyzing approximately 47 years of Supreme Court votes in the area of civil rights.
II.
SUPREME COURT RESEARCH ON ATTITUDINAL THEORY
Before becoming chief justice of the U.S. Supreme Court, Charles Evans Hughes observed that, “We are under a
Constitution, but the Constitution is what the judges say it is.” Several theories of judicial interpretation have
attempted to demonstrate a “personal element” in judicial decision making. This effort is the hallmark of the
“realistic” school of jurisprudence, which argues that law is “simply the behavior of the judge, that law is
secreted by judges as pearls are secreted by oysters” (Pritchett 1941, 890). The attitudinal model is the bedrock
theoretical principle of legal realists and is now clearly among the leading theories employed by scholars across
many disciplines to explain what transpires behind closed doors in the Supreme Court. What is intriguing about
the model is its deceptively simple but powerful logic: justices come to the Supreme Court with their ideological
preferences fully formed and, in light of contextual case facts, these preferences cast overwhelming influence on
their decision making (Segal and Spaeth 1993).1 Thus the attitudinal model is a complete and adequate model of
Supreme Court behavior, though not a complete explanation for justices’ votes.
The model has been widely tested and critiqued under a variety of conditions (see e.g., George and Epstein
1992; Epstein et al.1998; Sheehan, Mishler and Songer 1992). Evidence presented by these studies strongly
support the attitudinal model. However, we think that the potential theoretical importance of case salience in the
way the attitudinal model accounts for justices’ decisional calculations has received less than deserved attention
by both proponents and critics of the model.
In this paper, we make two basic arguments. First, case salience plays a moderating role that regulates the
ability of the attitudinal model to explain Supreme Court decisions. We think the primary reason why is that
1
Stylized facts suggest that the attitudinal model is most applicable to the merit votes of the
highest independent constitutional courts such as the U.S. Supreme Court (Segal and Spaeth 1994, 11).
The underlying assumption is that in these courts, justices can, and almost invariably do, rely completely
on ideological preferences for their votes. Justices have no electoral or political aspirations for a higher
office and their decisions cannot be overturned unless by a Constitutional amendment, which is difficult
to obtain. These institutional characteristics suggest that justices can freely, either consciously or
unconsciously, rely upon their personal values or preferences to guide their voting.
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issues raised in high salience cases reference justices’ attitudes more directly by raising justices’ interest and
attention in those cases to a higher level. Second, we argue that the attitudinal model explains high salience
cases better than it explains low salience ones. This is because issues presented in cases with high salience are
usually the most politically controversial, and they typically have larger policy ramifications than those raised in
cases with low salience. As a result, judicial attitudes are more easily tapped and relied heavily upon as referents
for deciding high salience cases. Recognizing the relevance of these two premises to the attitudinal model, we
think, is important for a deeper appreciation and understanding of the relative strengths of the model. Our
findings provide strong confirmation of our salience arguments and thus represent an important qualification
further crystallizing the attitudinal model.
While we recognize the value of studying the behavior of individual justices on the Court, our study here
takes a macro-analytic perspective. We are guided by the widely accepted view that judicial policy that
emanates from the Supreme Court is the result of a collective effort rather than the sum of individual positions.
Chief Justice William H. Rehnquist agrees when he observes that “Judging inevitably has a large individual
component in it, but [that] the individual contribution of a good judge is filtered through the deliberative process
of the Court as a body” (Rehnquist 1992, 270).
III. THEORETICAL UNDERPINNINGS OF A LINKAGE BETWEEN CASE SALIENCE AND
IDEOLOGICAL PREFERENCES
A. CONCEPTUALIZING CASE SALIENCE
We start by conceptualizing what a high salience case means. We define cases with high salience as
those that “stand out” in Supreme Court plenary agenda in the sense that they involve important issues of public
policy and therefore are likely to receive a disproportionate amount of attention and involvement from justices
throughout and from court-watchers, such as journalists.2 Segal and Spaeth (1996, 976) call such cases
“landmark” decisions for their being “more likely to establish precedential guidelines for future cases.” For
2
This definition of salience mirrors traditional political science definition of salience as
“importance.” In other disciplines such as social psychological, salience is defined as “the extent to which
a particular stimuli stand out relative to others in their environment” (Fiske and Taylor 1991, 246).
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sure, not all salient cases would necessarily generate progeny and proclaim legal prominence. In a broader
sense, cases that fail to generate progeny might themselves be highly politically salient. We accept the
suggestion raised by Cook (1993) and Brenner (1998) that case salience may operate at both political and legal
dimensions. Indeed, by our definition, Brown v. Board of Education (1954), which concerns school
desegregation, is widely recognized as a high salience case both politically and legally; it has produced wideranging structural impact in American public education, and has generated many progeny. However, Arlington
Heights v. Metro Housing Corporation (1977), which concerns social desegregation, is also politically salient
but not legally so because it has generated no progeny (Segal and Spaeth 1996, 993). Ideally, case salience is
best conceptualized by answering the question: How important is the case to a justice at the time the justice was
making the decision? Social scientists have no way of answering that question without direct access to Supreme
Court justices. Here we shall conceive of salience in the political sense.
B. CASE SALIENCE AS REFERENT FOR JUDICIAL ATTITUDES
Writing in the American Political Science Review long ago, C. Herman Pritchett emphasized the primacy of
judicial attitudes in jurisprudence and hints at their linkage to case salience: “justices of the Supreme Court, in
deciding controversial cases involving important issues of public policy, are influenced by biases and
philosophies of government [and] by ‘inarticulate major premises’ which to a large degree predetermine the
position they will take on a given question” (1941 p. 890). In essence, justices are more attuned to their inner
values in high salience cases than in low salience ones. But because law and social science follow inexact
principles and procedures of inquiry, it becomes a difficult matter to pinpoint with absolute certainty how case
salience references judicial attitudes.
We can begin to get a handle on this issue by examining as an example a fundamental aspect of
Supreme Court procedure that leads to final decisions on the merits: the process of majority opinion assignment.
After oral argument on a case, the Supreme Court holds a secret conference to discuss the case and cast tentative
votes based upon any number of factors including their ideological predilection, argument advanced by direct
and indirect parties, logic underlying the solicitor general’s position on the case. Following such votes, the chief
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justice would assign someone to write the majority opinion if the chief votes with the majority. If not, the most
senior associate justice in the majority would assign the opinion to any member of the majority coalition.
The attitudinal model has a role to play during opinion assignment. The basic assumption of the
attitudinal model is that the Court is “driven by single-minded seekers of legal policy, justices who wish to etch
into law their personal views” (George and Epstein 1992, 325). Within that context, research suggests that chief
justices and other majority opinion assigners typically reserve cases high in salience for themselves. For
example, finding variation in assignment among chiefs, Brenner (1993) concludes that during the 188 years
from 1801 (first year of Chief Justice John Marshall’s tenure) to 1989 (third year of William Rehnquist’s), chief
justices as a group self-assigned 35% of the majority opinions in salient cases, presumably higher than they selfassigned in all other cases combined. Such assignment pattern is important because it conveys something about
how chief justices approach their leadership roles. But more importantly for our purposes, it suggests a link
between case salience and the behavior of the chiefs. It is reasonable to assume that the majority opinion
assigner exercises substantial agenda control over the content of the opinion, which often determines the future
direction of law and policy on the subject. Consistent with the premise of the attitudinal model, self-assignment
allows the chiefs to write opinions that would best reflect directly their own set of values and preferences on the
case while maintaining the majority coalition (Rohde 1972; Slotnick 1978).3
The idea that chief justices behave differently in salient cases, in a way that references their ideological
values, is not to suggest that such behavior manifests itself only in chief justices. Among associate justices,
observational evidence suggests that ideological preferences are also referenced more when the case at hand is
of high salience than low salience. Journalists Fred Bardash and Joan Biskupic who cover the Supreme Court
for the Washington Post give the example of Justice Thurgood Marshall’s unwavering support for underdogs in
landmark civil rights cases. In such cases, “Marshall was utterly certain about where he stood, unyielding,
activist, and just a tad difficult” (Bardash and Biskupic 1993, 11). Empirical evidence suggests that other
associate justices exhibit similar tendencies in high salience cases (see Segal 1986).
3
There are other, more subjective, reasons why the chief may self-assign salient cases. For example, having the
chief justice as the opinion writer may bring “weight” to the opinion and help compliance.
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One way to recognize politically salient cases is through the number and diversity of interest groups
filling amicus curiae briefs in the case (Maltzmann and Wahlbeck 1996). These briefs provide useful
information for justices about the legal issues involved in the case and more importantly their policy relevance.
Information is an essential commodity for understanding case salience. A well known characteristic of case
salience is that the amount and variety of information available for consideration and analysis tend to increase
with case saliency (Caldiera and Wright 1988). With the increasing activism of interest representation in the
Supreme Court (Epstein et al. 1994, 581), justices must review and evaluate more and more material contained
in the information environment (e.g., case briefs, oral argument, and conference deliberation) and carefully
assess the potential impact of their decisions on mass political conflict. Such an assessment is critical especially
in cases that raise important policy concerns and are therefore likely to draw intense public scrutiny.
Important policy ramifications perceived by justices explain why, in salient cases, justices act with
greater interest, intensity, and motivation than they otherwise would. They ask more questions during oral
argument, press for greater clarity on key issues, and seek additional information beyond material in the briefs,
including information that, for strategic reasons, lawyers would disclose only because they must (Schubert et al.
1992). In high salience cases a justice’s position is relatively fixed and the chance is relatively low that new
information will change that position (Brenner and Palmer 1988). It is for this reason that Hagle and Spaeth
(1991) reported that fluidity is less likely in cases that are highly salient. In addition, we know from the Brennan
and Marshall papers that conference deliberations and intra-court bargaining are more intense when the case is
highly salient than when the case is not (Epstein and Knight 1998, 74). The value of the voluminous information
that typically accompany cases high in salience then is that it facilitates decision making by minimizing
uncertainty, reminding justices about the political and sociolegal importance of the case, and sharpening
justices’ references to their own personal values on the most pressing policy issues raised. Based upon the
foregoing discussion, we state the following salience hypotheses:
Salience hypothesis 1: Case salience conditions the explanatory capacity of ideological values in
Supreme Court voting.
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Salience hypothesis 2: Ideological values explain outcomes in high salience cases better than in low
salience ones.
C. CONTROL VARIABLES
We leverage our discussion of the importance of case salience in justices’ voting by introducing two control
variables suggested by the empirical literature. First, we use the solicitor general (SG) to account for the
signaling role of the executive branch in Supreme Court decision making. The SG serves as a conduit for
expressing the views, wishes, and frustrations of the executive branch to the Supreme Court. It is well known
that the SG, who is the quintessential repeat-player in the Court, enjoys a high success rate, both when
representing the federal government and when filing amicus curiae briefs on behalf of other litigants before the
Court (McGuire 1998). What is less well known is whether the SG is equally influential in high salience cases
and low salience ones. If as we argue justices are more attuned to their inner values in cases of high political
salience than in low salience ones, then consistent with the attitudinal model, we would expect the SG to exert
less influence on justices’ votes in high salience cases than in low salience ones.
Solicitor general hypothesis: The United States solicitor general exerts less influence on Supreme Court
decisions when the case is highly salient than when the case is not.
We also account for the active role that interest groups have traditionally played in the civil rights arena.
The number of interest group actively supporting or opposing civil rights claims of one kind or another has
increased dramatically since the assent of the Warren Court. We seek to evaluate the nature of the impact that
these groups have had on Supreme Court decisions. We address two questions regarding interest group
influence on the Court. First, are interest groups influential in Supreme Court decision making on the merits?
Empirical research on this question has reported mixed results (see Epstein 1991, 259-363). Second, do interest
groups exert less influence in high salience cases than in low salience cases? This question has never been
addressed in the literature. Instead, scholars have been preoccupied with the success of litigants before the
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Supreme Court (Lawrence 1990; Mishler, Songer and Sheehan 1992) and elsewhere (Unah 2003). We
believe that interest groups do engage in rational optimizing behavior. They will participate insofar as there are
benefits to be gained, whether in the form of merely obtaining political recognition for their causes or actually
winning cases on the merits. Generally speaking, we expect interest groups to have some influence on the Court
because justices find some utility in the arguments advanced by amici (Ivers and OConnor 1987). However, like
the SG, we expect interest groups to be less influential when the case is highly salient than when it is not.
Interest group hypothesis: Supreme Court justices are less likely to be influenced by interest
groups on the merits when the case is highly politically salient than when it is not.
IV.
DATA
We use data on civil rights cases decided by the Supreme Court during the 1953 through 2000 terms. This
represents 47 years of civil rights decision making in the Court. Civil rights cases constitute a broad
constitutional category, with cases involving mostly equal protection under the 14th Amendment but also some
aspects of the Bill of Rights, including defendant rights. Consequently, we think that our findings can be
generalized to other areas of Supreme Court jurisprudence such as the First Amendment. Appendix A shows the
diversity of issues covered by the data. These data were identified through the Supreme Court judicial database
(Spaeth 2000). These data are available at the Inter-University Consortium for Political and Social Research. We
use case citation as the unit of analysis. The lack of direct access to Supreme Court justices has produced several
attempts in political science to measure case salience through non justice-centered sources. The most recent
attempt was put forth by Epstein and Segal (2000). We rely on their measure of salience which is publication of
the Supreme Court decision on the front page of the New York Times. This measure has a temporal advantage
over previous measures because of its immediacy. The measure captures salience at almost the same time that
justices decide the case and newspapers dailies publish their analytic accounts of it.4
4. We assume that based upon the episodic nature of media coverage of the Court, cases receiving coverage on
the front page of the Times have previously received coverage, sometimes extensively, in the Times or in other
major national newspapers during the trial and appeal phases, thereby solidifying their potential political
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In measuring ideology, we join Epstein et al. (1998, 802) in making the now standard simplifying
assumption that a justice’s ideological value recorded at the time of appointment to the Court remains stable
thereafter. Based upon the updated Segal and Cover scores (Segal et al. 1995), we measured ideology as the
mean aggregate ideological value for all justices participating in the case, not just for justices in the majority
coalition.5 This measure has desirable qualities. First, the measure reflects the mean ideological orientation of
the Court’s membership as the case is being decided. Since justices in the minority coalition do have a voice in
the case, it is only fitting that a realistic measure of ideology should capture their voices as well as those of the
majority coalition. Moreover, this measure is consistent with Supreme Court norm. If for conflict of interest or
health reasons a justice fails to participate in the deliberation of a case, that justice has no influence in its
disposition. Second, the measure is consistent with prevailing attitudinal theory.6 One key advantage of our
model as reflected in this measure is that it is not static as would be a model based solely on case facts. Instead
our model is dynamic, reflecting how changing membership on the Court may shift ideological orientation and
thus sway outcomes of Court decisions. A measure relying on the median voter theory could also be appropriate
for this analysis. But a median voter measure would be weak as it cannot account for intensity of ideological
preferences among justices over civil rights. To lend greater credence to our findings, we shall validate our
salience well before the Supreme Court actually speaks.
5
In measuring ideology this way, we recognize that no measure of this construct is perfect. We focus on the
aggregated mean value as opposed to the value for the median justice because in addition to summarizing the
ideology of the justices, the mean also accounts for the interpersonal influences taking place amongst the
justices during their deliberation and decision making. Our measure does not account for changes in attitudes
during the justices’ tenures on the Court. We know for example, that Justice Blackmun dramatically shifted
his position on the death penalty from support in Furman v. Georgia (1972) to opposition in Callins v.
Collins (1994). But if attitude is a relatively stable construct, as psychologists assert, then long-term shifts
and occasional random punctuation in attitude cannot be ruled out entirely. Still, we think that relying on the
mean does not damage the explanatory capacity of the attitudinal model because the attitudinal model treats
attitudes as being exogenously determined (Segal and Spaeth 1993).
Under our measurement technique, for every “natural” court (period that starts with one personnel change
and ends with another), the mean ideological value is constant across all cases decided during that natural
court. However, because most justices serve across several natural courts during their tenure and because of
the extensive time period we examine (1953-2000), there is ample variation in the mean ideological values to
permit reliable results. Justices who were on the Court but failed to participate in a case due to illness or
whatever reason were not considered in calculating the mean ideological score for that case. Only under this
circumstance would the mean ideological index change in any given natural court.
6
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results by using the dynamic ideal point scores for median justices developed through computer simulation
by Martin and Quinn (2002).7
The dependent variable is whether justices supported a liberal (1) or a conservative outcome (0). A
liberal outcome is one that favors the rights of underdogs, minorities, and women; supports the individual
against the federal government; and supports the civil libertarian position in equal protection cases. Table 1
reports measurement and descriptive statistics of the variables.
********Table 1 about here********
Overall, N=934 with 56% of the cases decided in a liberal direction and 23% of the cases are reported as
being highly salient. Data on the SG and interest groups were derived through careful content analysis of
Supreme Court opinions in the U.S. Reports. We selected 25% of all racial discrimination and desegregation
cases and conducted inter-coder reliability assessment. That effort yielded reliability indexes for the variables
ranging from pi = .90 to pi = 1.00, which are excellent scores (Landis and Koch 1977). We conducted diagnostic
tests to determine the correlation of all the variables. Both the reliability indexes and the diagnostics suggest that
our data and findings are reliable and valid.
V. ANALYSIS
We begin with a careful look at the operational meaning of case salience by examining the publication attributes
of Supreme Court decisions on the front page of the New York Times. We are sensitive to the possibility that
front-page appearance on the Times may be biased in favor of cases from New York State and in favor of
liberal-oriented Supreme Court decisions.
A. POSSIBLE PUBLICATION BIASES IN THE NEW YORK TIMES MEASURE
Our examination of these possible publication biases is reported on Table 2. Section A examines possible bias in
favor of local cases. We find that roughly 42% of all civil rights cases directly involving New York State
litigants were published on the front page of the Times, whereas only about 23% of all cases involving litigants
from outside New York State were given front page coverage in the Times. The difference is statistically
7
The data are available at Andrew Martin’s homepage at http://adm.wustl.edu/
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significant (p < .05), suggesting that a publication bias in favor of local interests exists. But is the bias severe
enough to raise serious concerns that case origin might confound our overall findings? We conducted our
empirical analysis both with and without high salience cases from New York State. We find that high salience
cases from New York State are too few to make a substantive difference in the empirical results. Nevertheless,
we present here the more conservative results, which reflect exclusion of 13 high salience cases from New York
State. 8
[Table 2 about here]
The New York Times is typically associated with left-of-center viewpoints. Therefore, Table 2B
examines whether the Times disproportionately favors liberal Supreme Court decisions for front-page coverage.
The analysis shows that roughly 28% of liberal decisions were published on the front page of the Times during
our period of inquiry, whereas 19% of conservative decisions were published on the front page. The difference
is also statistically significant (p<.01), suggesting that a liberal bias exists in New York Times designation of
civil rights cases for front page prominence. We conclude that the New York Times measure of salience is
imperfect but for its immediacy represents a marked improvement over other measures of salience currently in
existence.
B. THE CONDITIONAL EFFECT OF CASE SALIENCE ON THE ATTITUDINAL MODEL
Table 3 presents results examining our hypothesis that the explanatory capacity of the attitudinal model is
conditioned by case salience. Methodologically, this hypothesis requires an interaction model, which further
implies that the resulting coefficients describe conditional as opposed to additive relationships (Friedrich 1982).
[Table 3 about here]
8
Compared to model 1 reported in Table 3, there is only a slight change in the salience and the
interaction coefficients when highly salient New York State cases are included in the model. The results
are as follows: Pr (liberal decision) = .152 + 1.201 (mean ideology) + .398(high salience) + 1.1206 (mean
ideology * high salience). All the variables are statistically significant at the .05 level or better; pseudo R2
= .067; N = 929 and 58% of the cases are predicted correctly. Clearly, the substantive story remains
unchanged.
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Generally speaking, the results indicate a fair amount of predictive validity of the measures. Virtually
all the variables are statistically significant and in the expected direction, correctly predicting a reasonable
amount, and in some instances a great deal, of the variance in Supreme Court liberalism. Model 1 is the base in
this table; it includes only the mean aggregate ideology measure, case salience and their interaction. All
variables are statistically significant at the .05 level or better. The model explains 57% of the cases correctly and
this represents a slight improvement over the null. When the mean aggregate ideology of justices sitting to
decide a case is high (i.e., when the Court is highly liberal), the probability is 77% that the Supreme Court will
decide the civil rights cases in a liberal direction. This is hardly a big surprise. According to the attitudinal
model, on average, liberal justices would tend to vote liberally and conservative justices conservatively. Our
primary interest however is to untangle the possible role that case salience plays in this pattern of behavior. We
include a dummy variable for high salience and find that all things being equal, high salience cases are 60%
more likely to be decided liberally compared to low salience cases. Importantly, there is a statistically significant
interaction between judicial ideology and case salience, providing initial support for our argument that the role
of ideology in Supreme Court decision making is regulated by the salience of the case. Model 2 confirms these
findings, using the dynamic ideal point scores of median justices. These scores appear to be valid surrogates for
our mean ideology measure.9
The base model may not be able to capture the full complexity of the relationship between ideology and
case salience in Supreme Court decision making. In model 3, we add control variables to the basic model for a
more complete and rigorous test of our conditional effect hypothesis. The main effects of ideology and case
salience remain statistically significant. And once again, the two factors evince codependent explanations. We
can state definitively that the effect of ideology is regulated by the salience of the case. When a case is highly
politically salient, the attitudinal model predicts that the Supreme Court is 71% more likely to rule liberally in
that case, holding other variables constant. We believe the reason for this outcome is that case salience
references the values of the justices more directly. It is important to evaluate this explanation in light of the
9 Because amici volume in a Supreme Court case can be considered an indicator of case importance, we re-estimated our
models using amici volume as indicator of salience. The results were not consistent across models. We therefore decided to
rely upon the New York Times measure throughout.
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issues raised in civil rights cases and their level of political salience. Figure 1 reports Supreme Court
dispositions and the level of political salience for various civil rights issues. The most salient and controversial
civil rights issues over the last five decades are racial in nature, including desegregation, discrimination, and
voting rights. These are valence issues with much ideological content, issues where even conservatives can
sometimes find reasons to disagree amongst themselves. Moreover, they are issues in which, within a political
climate reasonably motivated to dismantle obstacles to economic and social justice, the “correct” constitutional
answer is often to err on the side of equal protection for the underdog.
[Figure 1 about here]
For the solicitor general, a number of interesting findings emerge. The SG participates in 63% of civil
rights cases argued in the Supreme Court during our period of study, most of those coming during the Warren
and Burger Courts. Moreover, the SG files more conservative briefs in the Court (35%) than liberal briefs
(28%). Compared to the Warren and Burger Courts, there is a steep decline in the number of civil rights cases
coming to the Rehnquist Court as this Court is perceived as being hostile to liberal claimants. This decline is
partly reflected in the direction of SG briefs. From 1986 to 2000, the SG sent only 8 liberal briefs to the
Rehnquist Court; the rest (42) were conservative. In other words, 79% of all civil rights briefs sent by the SG to
the Rehnquist Court were conservative, even though this period includes eight years in which a Democratic
president, Bill Clinton, occupied the White House. But does the SG actually sway Supreme Court decisions on
the merits? Studies suggest the answer is yes. We agree.
We find that the Court is 67% more likely to rule in a liberal direction when the SG files a liberal brief
compared to a conservative brief or no brief at all. However, this influence is contingent upon the level of
interest group participation in the case. About 25% of the cases have no amicus participation whatsoever. The
average Supreme Court case has three amicus briefs. However, the case of United States v. Morisson (2000)
received 55 amicus briefs, the highest in our data set. In that case the Court upheld the constitutionality of
federal civil remedies for victims of gender-motivated violence. We disaggregated the interest group influence
by constructing a dummy variable for the presence in the case of either the NAACP or the ACLU (or both) and
a continuous variable for all other amici. We selected the two left-of-center organizations for their public
16
visibility and sustained effort to restructure institutional civil rights agenda in the Supreme Court (Barker
1967). We find that the presence of these organizations in the case leads to a liberal outcome 57% of the time.
The effect of other amici, however, is contingent upon the nature of SG stance in the case. When there is a high
number of amici in a case and the SG files a liberal brief, the Supreme Court is less likely to decide that case in a
liberal direction. We think this is because the many amici voices tend to cancel out the relatively less frequent
liberal voice of the SG in the Court.
Model 4 reports confirmatory results except the outcome for the interest group variables. In this model
we rely on the dynamic ideal point median as a measure of ideology. The interaction between the Court median
and high salience evinces statistical significance, confirming our original salience hypothesis. What is different,
however, is that liberal organizations no longer exert significant influence whereas the presence of a large
number of other amici tends to reduce the likelihood of a liberal outcome. We can conclude from the foregoing
analysis that there is strong support for our conditional salience hypothesis: case salience strongly regulates the
ability of the attitudinal model to explain judicial votes in the Supreme Court at least in the broad area of civil
rights.
C. THE ATTITUDINAL MODEL IN HIGH SALIENCE VS. LOW SALIENCE CONTEXTS
How does the attitudinal model compare in high salience and low salience contexts? A simple correlation
analysis indicates a stronger relationship between ideology and Supreme Court liberalism under conditions of
high salience (r=.38, p<.001) than under conditions of low salience (r=.18, p<.001). In Table 4, we further
examine the role of case salience by subjecting the data to a different analytical scheme as a way of validating
and contextualizing the salience results reported above. We disaggregated the data into high salience and low
salience cases for logistic analysis, adding SG and interest group controls. Our primary objective here is to test
our second salience hypothesis that the attitudinal model explains a higher proportion of high salience cases than
low salience ones. If this is the case, ideology should evince a higher impact on Supreme Court liberalism in
high salience cases than in low salience ones. Model 5 uses high salience cases alone. Here, 72% of the variance
is correctly predicted with a 20% reduction in error, suggesting that we can place a high degree of confidence in
17
the results. When the Court is highly liberal, the predicted probability of a liberal outcome is 90% if the case
is highly politically salient. We can compare this finding to the low salience context in model 7. While mean
ideology remains statistically significant, the coefficient drops and the predicted probability of a liberal outcome
drops to 82% when the case is of low salience.10
[Table 4 about here]
Since no measure of Supreme Court ideology is perfect, we estimated models 6 and 8, relying on the
ideal point of the Court’s median as an alternative measure of ideology. Doing this lends further credence to our
salience argument and finding that ideology explains decisions better in high salience cases than in low salience
ones. The predicted probability of a liberal outcome is 79% when the case is highly salient; it drops to 62%
when the case is not. We next examine whether the differences between the predicted probabilities are
meaningful. Figure 2a is a graph of the predicted probabilities under both high salience (model5) and low
salience (model 7) contexts when only mean aggregate ideology is allowed to vary and all other variables are
held constant at their means.11 The figure shows that the predicted probability of a liberal outcome for both
models increases steadily as the Supreme Court becomes more liberal. This is indeed what the attitudinal model
predicts. But notice that the high salience line has a steeper slope, indicating that ideology serves as a stronger
decisional referent in high salience cases than in low salience ones. For sure the Supreme Court does not simply
vote liberally in all high salience cases. This is indicated in the figure as well. A highly conservative Court is
less likely to vote liberally in high salience cases than in low salience ones.
[Figure 2a and 2b about here]
Figure 2b depicts the predicted probabilities of a liberal outcome across different dynamic ideal points
of the Court’s median in high salience cases (models 6) and in low salience ones (model 8). Once again the
10 We also controlled for the possibility that the effect of case salience is time-sensitive by including a time
counter coded 0 for cases decided in 1953, 1 for cases decided in 1954...., incremented to cases decided in
2000. In both models, the time variable failed to evince statistical significance and other coefficients
remained unchanged. Because time is neither a theoretically interesting nor substantively meaningful
variable, we decided to remove it from the final results.
11 This analysis was performed using Clarify: Software for Interpreting and Presenting Statistical Results,
version 2.1. CLARIFY is available at http://gking.harvard.edu. We thank Gary king of Harvard University,
Michael Tomz of Stanford University, and Jason Wattenberg of the University of Wisconsin for making
18
figure confirms that ideology is a stronger decisional referent in high salience cases than in low salience
ones. In very conservative courts, the probability of a liberal outcome is clearly lower in high salience cases than
in low salience ones. However, as the Court gets more liberal, the probability of a liberal outcome increases
faster in high salience cases than it does in low salience ones.
D. IS THE U.S. SOLICITOR GENERAL LESS INFLUENTIAL IN HIGH SALIENCE CASES?
We have reported that the SG is generally quite effective and influential in the Supreme Court. Here we explore
further the implications of the SG’s success. The interesting question now is whether case salience matters in the
SG’s capacity to influence justices. Our analysis shows that although the government’s lawyer is influential in
both high salience and low salience cases, the SG is, on balance, significantly less influential when it comes to
high salience cases. When the SG is on record advocating a liberal position, the probability is 71% that the
Court will vote in support of that position when the case is of low political salience. However, in cases of high
political salience, the probability that the Court would agree with the SG drops to 56%. To complicate matters,
this finding is contingent upon the nature of the position taken by organized interests. In high salience cases, the
SG’s influence is enhanced when the NAACP or the ACLU take a stance similar to the SG and when the
number of other amici voicing an opinion in a particular case is large rather than small. In low salience cases,
however, the SG’s ability to sway justices in a liberal direction is enhanced when the NAACP or the ACLU take
a position similar to the SG. But the direction of influence reverses when there are more amici similarly vying
for influence in the Court.
This finding that the Supreme Court is less influential in high salience cases has policy implications for the
executive branch. If as McGuire (1998, 522) suggests that litigation expertise is the one currency that truly
distinguishes the government’s lawyer from other repeat players in terms of success in Supreme Court
advocacy, then it stands to reason that the SG’s expertise may not yield as much dividend for the executive
branch in salient cases as one might have thought. By their very nature, high salience cases represent instances
where the preferences of justices are most likely to come into conflict with values expressed by presidential
CLARIFY available to us.
19
administrations. Thus, in high salience cases, the executive branch and its chief advocate face a far more
arduous task of legal persuasion than they do in “normal” cases. We have no reason to doubt the application of
this result to nongovernmental legal advocates before the Court. In high salience cases, justices are generally
more demanding and more skeptical of legal arguments proffered by lawyers than they are in low salience cases.
Therefore, to achieve important policy objectives through legal means, the SG must try harder and be more
forceful because the federal government stands at the mercy of the Supreme Court to interpret the law in its
favor.
We included a control variable to account for interest group influence on justices’ votes. An important
aspect of interest group litigation is the question of effectiveness. To what extent are groups efficacious in their
effort to influence the decisions of Supreme Court justices? Much of the literature suggests that groups are not
effective beyond the certiorari stage of decision making. After all, in handing down decisions of national scope,
the argument goes, justices face no electoral or political incentives that would position them to be swayed by
organized pressure. However, we do find evidence supporting Bentley’s (1908, 338) old claim of there being
“numerous instances of the same group pressures which operate through executives and legislatures, operating
also through [the] Supreme Court.” When interest group influence is disaggregated to identify the most visible
repeat players in an issues area, groups do exert effective influence on the Court’s decisions on the merits.
Interestingly, the degree of influence is not contingent upon the salience of the case as we originally thought it
would. The ACLU and NAACP are among several interest organizations pressing a political agenda in the
Supreme Court. In the civil rights policy domain, they hold a unique position of visibility. These liberal groups
bring substantial expertise and issue-based credibility to their defense of cherished liberties and rights. It is little
wonder then that they are successful in exerting some influence on the Supreme Court on the merits.
VI. CONCLUSION
This study was motivated by twin objectives. We wanted to know whether or not the explanatory capacity of the
attitudinal model of judicial behavior is conditioned by case salience and whether the model holds equally true
in high salience and low salience cases in the U.S. Supreme Court. These represent significant issues for
20
scholars of law and courts because both proponents and detractors of behavioral theory have not
systematically accounted for the role of case salience in how the attitudinal model explains Court decisions.
Upon closer examination, it turns out that the attitudinal model is indeed sensitive to case salience and that the
model is more capable of explaining high salience cases before the Supreme Court than low salience ones. In
high salience cases, justices vote primarily their attitudes regardless of the information provided by the solicitor
general or interest groups. We also find that despite all the talk about the amazing success and influence of the
government’s lawyer in the Supreme Court, that influence is more nuanced, more complex than previously
thought. The SG is actually less influential in high salience cases than in those low in salience. This is entirely
consistent with the primacy of attitudes in Supreme Court decision making. Given the diverse nature of civil
rights cases and our rigorous analytical method, we think that our findings can apply to other areas of Supreme
Court jurisdiction such as criminal procedure and the right to privacy.
Beyond what our findings have to say about the attitudinal model, the analysis also has implications for
rival theories of Supreme Court decision making, notably the legal model. The linchpin of the legal model is
justices’ claimed reliance on stare decisis. Nothing in our analysis would suggest that reliance on precedent is
altogether dead in the Supreme Court, even as scholars continue to debate the relative merits of the legal and
attitudinal models. Nevertheless, Spaeth and Segal (1999, 309) have presented correlational evidence for the
idea that precedent plays a stronger role in the least salient of the Court’s cases than it does in landmark cases.
Our analysis supports that conclusion insofar as to show that the attitudinal model possesses a higher predictive
and explanatory capacity in high salience cases than in low salience ones. Among the important considerations
in anticipating the decisions of the U.S. Supreme Court are justices’ ideological orientations and case salience.
We think that our research further contextualizes scholarly understanding of the explanatory potential of the
attitudinal model and that our findings represent a highly important qualification to the model.
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25
Table 1
Variable
Supreme Court
decision
(N=934)
Mean aggregate
ideology
(N=930)
Court median
(N=934)
Solicitor general
(N=919)
NAACP/ACLU
(N=934)
Other amici
(N=933)
Case salience
(N=934)
Measurement and Source
1: Liberal
0: Conservative
(Harold J. Spaeth, ICPSR #9422 )
Average ideological value of all justices voting in the
case (Segal et al. 1995, 816). Negative values denote a
conservative Court.
Dynamic ideal point of the Court’s median justice
(Martin and Quinn 2002)
-1: Participates with a conservative brief
0: No brief
1: Liberal brief
1: NAACP and/or ACLU participates as direct
party or as amicus curiae
0: Otherwise
Sum of all amici (net of NAACP and/or ACLU)
Mean
Min.
Max.
.56
0
1
.007
-.56
.66
-.38
-1.026
.843
-.06
-1
1
.29
0
1
3.25
0
55
0
1
1: Case decision reported on the front page
.23
of the New York Times
0: Case decision not reported on the front
page of the New York Times
(Epstein and Segal 2000)
Where source is not indicated, the authors are the source of the data and coding.
26
Table 2A
Publication Attributes of U.S. Supreme Court Decisions in the New York Times
NEW YORK CASE
No
Yes
Total
New York Times Coverage
Front page
13 (41.9%)
211 (23.4%)
224 (24%)
Not front page
18 (58.1%)
691 (76.6%)
709(76%)
Total
31 (100%)
902 (100%)
933 (100%)
Note: A chi square test of association suggests that Supreme Court cases that originate from New
York State are significantly more likely to be published on the front page of the New York Times
than cases from outside New York State. Chi square = 5.65, p<.05.
Table 2B
SUPREME COURT DECISION
Liberal
Conservative
Total
New York Times Coverage
Front page
145 (27.7%)
79 (19.3%)
224 (24%)
Not front page
378 (72.3%)
331 (80.7%)
709 (76%)
Total
523 (100%)
410 (100%)
933 (100%)
Note: A chi square test of association reveals that the New York Times is more likely to reserve
front page coverage to liberal Supreme Court decisions than conservative decisions. Chi square =
9.008, p<.01.
27
Appendix A: Diversity of Civil Rights Issues Addressed in the U.S. Supreme Court, 1953-2000
The issue groupings cover all areas of civil rights. We make every effort to group together issues of substantive and
historical similarity. Our groupings are constructed according to the issue identification number listed in the U.S. Supreme
Court judicial database code book. Overall, there are 934 cases.
Identification
number
Description
Number of
cases
Desegregation
220
221
230
Desegregation (social)
School desegregation
Sit-in demonstrations
51
40
18
Discrimination
222
223
272
283
284
Employment discrimination
Affirmative action
Employability of aliens
Sex discrimination (non-employment)
Sex discrimination in employment
60
19
11
37
28
Immigration
271
371
372
373
374
375
376
Deportation
Permanent residence
Citizenship
Loss of citizenship (denaturalization)
Access to public education
Access to welfare benefits
Miscellaneous immigration issues
53
1
6
20
3
2
2
Indigents
261
381
382
383
384
386
387
388
Debtor=s rights
Appointment of counsel
Inadequate representation
Payment of fines
Filing fees
Transcript
Assistance of psychiatrist
Miscellaneous indigent issues
13
8
4
4
14
14
1
5
Military
361
362
363
Military draftee/induction
Active duty
Veteran
6
30
17
Voting
210
211
212
250
Voting
Voting Rights Act of 1965, plus amendments
Ballot access (of individuals and candidates)
Reapportionment
27
37
19
53
Welfare
311
312
321
331
341
Welfare benefits (constitutional)
Welfare benefits (statutory)
Inheritance, survivor, and paternity benefits
Rights of handicapped
Residency requirements
33
41
18
21
21
Miscellaneous Civil
293
294
301
391
399
American Indians
State jurisdiction over American Indians
Juveniles
Liability based on civil rights acts
Miscellaneous civil rights
27
58
20
89
3
Issue
28
Table 3
Effect of Case Salience and Ideological Orientation on Civil Rights Liberalism in the Supreme Court, 1953-2000
Model 1
Model 2
Model 3
Model 4
β (S.E.)
Predicted
β (S.E.)
Predicted
β (S.E.)
Predicted
β (S.E.)
Probability
Probability
Probability
Mean ideology
1.204***
.77
1.405***
.80
(.252)
(.278)
Case salience
.390**
.60
.842***
.70
.286*
.57
.789***
(.175)
(.253)
(.196)
(.269)
Mean ideology * case salience
1.230**
.77
.922**
.71
(.531)
(.566)
Court median
.623***
.65
.491***
(.173)
(.179)
Court median * case salience
1.082***
.75
.901**
(.407)
(.428)
Solicitor general
.719***
.67
.612***
(.127)
(.124)
LDF/ACLU
.277**
.57
.192
(.168)
(.165)
Other amici
-.021
.49
-.042***
(.015)
(.014)
LDF/ACLU * solicitor general
.143
.53
.170
(.217)
(.214)
Other amici * solicitor general
-.030**
.49
-.031**
(.015)
(.016)
Constant
.153**
-.395***
-.244***
-.479***
(.077)
(.107)
(.099)
(.121)
Number of cases
916
920
900
904
-2*LLR =
1192***
1209***
1112***
1141***
Correctly predicted
57.5
54.6
63.7
65.0
Reduction in error
.04
-.18
.20
Note: Entries are logistic estimates. Cases from New York State that were published on the front page of The New York Times
were removed from analysis reported on this table. Predicted probability = odds ratio/[1+ odds ratio], where odds ratio is the
exponential of the logistic coefficient.
Predicted
Probability
.69
.62
.71
.65
.55
.48
.54
.49
--
29
Table 4
Effects of Ideological Orientation, Solicitor General, and Interest Groups on Liberalism in High Salience and Low-salience Contexts, 1953-2000
HIGH SALIENCE CONTEXT
LOW SALIENCE CONTEXT
Model 5
Model 6
Model 7
Model 8
β (S.E.)
Predicted
β (S.E.)
Predicted
β (S.E.)
Predicted
β (S.E.)
Predicted
Probability
Probability
Probability
Probability
Mean ideology
2.161**
.90
1.518***
.82
(.960)
(.345)
Court median
1.329** .79
.486*** .62
(.570)
(.119)
Solicitor general
.237*** .56
.128
.53
.879***
.71
.760*** .68
(.028)
(.139)
(.088)
(.099)
LDF/ACLU
.450**
.61
.323*
.58
.222***
.55
.160*** .54
(.215)
(.203)
(.043)
(.016)
Other amici
-.038**
.49
-.050*** .49
-.009
.50
-.037*
.49
(.017)
(.009)
(.032)
(.026)
LDF/ACLU * Solicitor general
.254*** .56
.225**
.56
.189***
.55
.261*** .56
(.087)
(.131)
(.065)
(.034)
Other amici * Solicitor general
.008*** .50
.005
.50
-.062***
.48
-.057*** .49
(.002)
(.004)
(.023)
(.022)
Constant
.567*** -1.244*** -.260***
-.500*** -(.128)
(.0812)
(.073)
(.113)
Number of cases
218
219
695
698
-2*LLR =
237.02***
244.06***
881.38***
906.26***
Correctly predicted
.72
.69
.62
.64
Reduction in error
.20
.10
.20
.24
Note: Entries are logistic estimates. Standard errors are adjusted for clustering on solicitor general. Predicted probability = odds
ratio/[1+ odds ratio], where odds ratio is the exponential of the logistic coefficient.
30
Figure 1: Civil Rights Liberalism and Issue Salience, 1953-2000
80
70
60
Percent
50
40
41.3
41.3
Liberal
Conservative
High Salience
34.6
30
26.4
20
16.4
11.5
10.2
10
3.3
0
De
s
eg
reg
Dis
ati
on
cri
m
ina
ti o
n
Vo
tin
g
Mi
lita
ry
Issue
We
l fa
re
Im
mi
gra
t
Mi
ion
Ind
sc
ige
ell
nt
an
eo
us
31
Figure 2a: Effect of Mean Aggregate Supreme Court Ideology on Liberalism in High Salience
vs. Low Salience Contexts
1
Predicted Probability of a Liberal Outcome
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
96 0.86 0.76 0.66 0.56 0.46 0.36 0.26 0.16 0.06 0.04 0.14 0.24 0.34 0.44 0.54 0.64 0.74 0.84 0.94
-0.
Mean Aggregate Supreme Court Ideology
High Salience
Low Salience
32
Figure 2b: Effect of Dynamic Ideal Point Median on Liberalism in High Salience vs. Low
Salience Contexts
1
Predicted Probability of a Liberal Outcome
0.9
0.8
0.7
0.6
High Salience
Low Salience
0.5
0.4
0.3
0.2
0.1
0
-1.
3
1
-1.
9
-0.
-0.
7
3
1
5
0.5
0.7
0.3
0.1
-0.
-0.
-0.
Dynamic Ideal Point Median of the Supreme Court
0.9
1.1
1.3