Offense, Defense, and the Causes of Civil War Recurrence:
The Effect of External Military Support on Peace Duration
By Jordan Roberts
Previous literature addressing the phenomenon of civil war recurrence has examined the domestic sources of
recurring civil wars, but has not adequately assessed the impact of external military support on civil war recurrence.
This project seeks to fill that gap by assessing the impact of external support on the peace duration of post-conflict
countries, paying specific attention to the effects of foreign-supplied offensive and defensive military technology.
The theory presented in this project was largely inspired by the offense-defense theory (ODT) literature. While
traditional ODT is primarily concerned with the technological superiority of offense or defense in the international system, this project examines the availability of externally provided offensive and defensive technologies
within a post-conflict country, and the impact of such availability on the durability of peace. Using a series of
proportional hazards models, this project finds that the availability of offensive types of support decreases the
duration of peace, while the availability of defensive types of support increases the duration of peace. This finding
provides a strong case for distinguishing between support that is offensive and defensive.
R
INTRODUCTION
suffering, and the contribution made by this project will allow better prediction of this event. This improved predictive capability will better empower
policymakers and peacekeepers to prevent such violence before it occurs.
The remainder of this project will be organized into the following sections: 1) the literature review; 2) the theory and hypotheses; 3) the research
design; 4) the results and analysis; and 5) policy implications and avenues
for future research.
ecurring civil wars are a chronic source of violence, suffering, and
pain for many people. For some countries, the cycle of violence
seems inescapable. In many cases, the violence within the borders
of a state are heavily funded and supported by actors outside those borders.
This phenomenon is the impetus for this project, which seeks an answer to
the following questions: What role does external military support play in
civil war recurrence? Why do some cases of external support reignite conflict,
LITERATURE REVIEW
while others do not?
This project seeks to fill two major gaps in the
This literature review will be organized into three
literature regarding civil wars. First, while the
major sections: 1) a review of literature addressing
literature has examined the role of external support “Improved predictive capability will
external support in civil wars (my independent variin civil wars, empirical studies have not operation- better empower policymakers and
able of interest); 2) a review of literature addressing
alized external support as a primary explanatory
civil war recurrence (my dependent variable); and
peacekeepers to prevent such
variable. Second, most work focusing on external
3) a review of offense-defense theory (which is the
violence before it occurs.”
support has investigated its effect on civil war onset
basis of the causal logic linking my independent and
or civil war termination, while neglecting a full
dependent variables).
exploration of external support’s impact on civil war
recurrence. Additionally, by linking external support to civil war recurrence External Support
using the ideas of offensive and defensive technologies, this project applies
the logic of offense-defense theory (ODT) to a domain it has not yet been “External support” consists of military resources provided to a warring
extended to. Furthermore, this project has relevance for contemporary party or potential combatant within a given country by an actor located
global affairs. Civil war recurrence is a significant source of human outside the borders of that country. There exists a wide variety of literature
28
The Hinckley Journal of Politics 2014
concerning the role of external support in civil war. This literature explores conditions that impact the likelihood of civil war recurrence at multiple
such topics as what type of rebel groups receive support, the roles of ethnic levels of analysis. Quinn, Mason, and Gurses conceptualize civil war recurties in sponsorship, and even how support can increase the likelihood of rence as having two necessary conditions—one structure-based, one
interstate conflict between a sponsor state and the state fighting the sponsored agency-based (2007). The necessary structural condition is dual soverparty (Gleditsch, 2007; Salehyan, 2008; Salehyan, Gleditsch, & Cunningham, eignty—which is present when a group other than the state possesses the
2011). In a seminal article in the study of civil wars, Fearon and Laitin capacity to challenge the state’s claim to sovereign authority. If the condition
(2003) found that foreign sponsorship significantly increased the probabil- of duel sovereignty is not attained, no effective opposition to the state exists,
ity of civil war onset. This is intuitive given that rebel groups are typically and thus, no civil war could occur. The necessary agency-based condition
funded by donations from foreign states and diasporas, not by the popula- is that the expected utility of war is higher than the expected utility of peace
tion of the warring country (Collier et al., 2003). Despite the widespread for at least one of the potential combatants. If this condition is not met,
interest in the role of foreign sponsors, inadequate attention has been paid then no rational potential combatant would initiate war. Walter (2004)
to the role external support plays in civil war recurrence and the different conceptualizes civil war recurrence as a product of individual-level decicategories of support sponsors can provide.
sions—specifically, whether or not to join a rebel organization—based on
While the various types of support sponsors can provide has received quality of life and the ability to affect politics though non-violent means.
little attention in the quantitatively-oriented literature, there has been some
Neither Quinn, Mason, and Gurses, nor Walter explore the role of
notable work that disaggregates general support into its primary subcatego- foreign sponsors in civil war recurrence. This ought to have occurred, given
ries in the qualitative literature. Perhaps the most systematic attempt was that foreign sponsors have the capability to affect conditions of structure
undertaken by Byman et al. (2001), who not only divided foreign support (by reestablishing dual sovereignty via increasing the capacity of opposition
into ten categories, but also established a hierarchy for understanding the groups) and conditions of agency (by altering the cost-benefit analysis of
varying degrees of significance these categories of support have in bolster- both combatant groups and individuals—the decision-making agents in
ing an insurgency. While the categorization scheme Byman et al. established the two models mentioned above). The purpose of this project is thus to
makes many useful contributions to how we conceptualize external support, address the aforementioned gaps in the literature by assessing the impact
it does not employ an offense or defense distinction similar to the one I of foreign sponsorship on civil war recurrence.
propose here.
A prominent article concerning foreign sponsors in civil war notes Offense-Defense Theory
(when summarizing the finding of previous work): “Civil wars with outside
involvement typically last longer, cause more fatalities, and are more difficult This project will link external support to civil war recurrence through a
to resolve through negotiations” (Salehyan, Gleditsch, & Cunningham, theory that is partially inspired by offense-defense theory (ODT). The
central claim of ODT is that war is more likely to
2011). Given that the literature has produced such
occur when offense has the military advantage than
unequivocal findings concerning the impact of
when
defense has the military advantage. In other
external support on civil war, it is surprising that
“The
literature
on
civil
war
recurwords,
an offense-defense balance (ODB) tilted
the role of external support in civil war recurrence
toward
the
offense exacerbates the security dilemma,
has not been explored to a greater extent.
rence has established a laundry list
while
an
ODB
tilted toward the defense ameliorates
of factors that influence a return to
Civil War Recurrence and Peace Duration
it. When attacking is easier than defending, even
conflict: the amount of time
status quo powers, who merely seek security maxielapsed since the previous war, the
Throughout this paper, I use the terms civil war
mization, are incentivized to take aggressive actions
outcome of the previous conflict,
recurrence and peace duration interchangeably, as
(Jervis, 1978; Van Evera, 1998). Furthermore, these
they are essentially two sides of the same coin. Civil
the presence of peacekeeping forces
undesirable effects of offense-dominance are selfwar recurrence refers to civil war happening after a
reinforcing
and difficult to escape (Van Evera, 1998).
post-conflict, duration of the
period of peace since the previous war. Peace duraWhile
ODT
is primarily concerned with examprevious war, size of the governtion refers to the amount of time between the end
ining states interacting in the international system,
ment’s post-war military, number
of the initial war and the start of the recurring war.
the concept of the ODB has also been applied to
of fatalities in the previous war,
The probability of civil war recurrence is inversely
ethnic civil wars (Kaufmann, 1996; Posen, 1993).
level of economic development,
related to the expected peace duration by definition
ODT, however, has not been effectively applied to
(as the probability and recurrence increases, the
partition of the state, and proxies
non-ethnic civil war, due to the assumption that the
expected duration of peace decrease).
ODB
is only relevant for nationalistic groups (Posen,
for the quality of life such as infant
The literature on civil war recurrence has estab1993).
As the underlying logic of ODT concerns
mortality.”
lished a laundry list of factors that influence a return
structural incentives faced by actors that think strato conflict: the amount of time elapsed since the previous war, the outcome tegically about those incentives, there is no reason the theory’s logic could
of the previous conflict, the presence of peacekeeping forces post-conflict, not be applied to any identifiable group that acts in such a manner—regardduration of the previous war, size of the government’s post-war military, less of whether the group is a nation or has nationalistic tendencies.
number of fatalities in the previous war, level of economic development, Furthermore, Posen’s study chooses a measurement of the ODB that pripartition of the state, and proxies for the quality of life such as infant oritizes group cohesion over military assets because Posen (1993) assumes
mortality (Collier & Hoeffler, 2004; Quinn, Mason, & Gurses, 2007; Walter, that the military assets possessed by sub-national groups are usually meager,
2004). This list reveals an important shortcoming in the civil war recurrence and that cohesion is a more significant determinant of offensive capability.
literature—the inadequate consideration of transnational factors (the only While this could have been true for the cases Posen studied (ethnic wars in
one in the above list is the presence of peacekeeping forces post-conflict). post-Soviet states), there is no reason to assume that this is generally true
This gap seems peculiar given the rich literature on foreign sponsors and of civil wars. External military support from foreign states provides military
war onset (discussed in the previous section). Authors have identified assets that—while not usually “cutting-edge” quality by great power
29
Offense, Defense, and the Causes of Civil War Recurrence
Jordan Roberts
standards—can significantly alter the relative power of the combatants in
the war and the technological advantage of offense within a country.
While there have been multiple notable criticisms of ODT, these criticisms have at least partially relied on refuting ODT’s claims about offensive
or defensive superiority in the international system (Gortzak, Haftel, &
Sweeney, 2005; Levy, 1984; Lieber, 2000). As will be made clear in the next
section, this study proposes an alternative national-level conception of ODT
that focuses on the availability, not the superiority, of offensive and defensive military technologies.
would-be warring party.2 The presence of external military support increases the probability that these necessary conditions are fulfilled. Of additional importance to the theory proposed below, the condition of dual
sovereignty enables the application of a modified ODT to the “domestic
system” (as opposed to the international system). This is because the lack
of a single viable sovereign authority shifts the ordering principle of the
domestic system from approximating the ideal-type of hierarchy to approximating the ideal-type of anarchy.3 The development of dual sovereignty
is essentially emergent anarchy and an anarchic system is a precondition
for the operation of the offense-defense balance.
THEORY AND HYPOTHESES
For the reestablishment of dual sovereignty to occur, the opposition
must become sufficiently powerful to challenge the state’s claim to sovereign
This project rests on the fundamental premise that cases of civil war recur- authority. While many domestic factors can influence the strength of the
rence are theoretically distinct from cases of first-time civil war onset. Simply opposition, foreign intervention can have dramatic effects on the relative
coding cases of civil war recurrence as civil war onset ignores the unique capabilities of the combatants (Regan, 2000). Foreign support in the form
properties of recurring civil wars, some of which are grounded in the notion of military equipment and foreign fighters in particular dramatically
of the “the conflict trap” (Collier & Sambanis, 2002; Collier et al., 2003). A increases the ability of an opposition group to challenge the state. For war
country is caught in a conflict trap when a previous civil war has established reignition to become rational for a potential combatant group, the expecta post-conflict environment that predisposes the
ed utility of war must be greater than the expected
country to experience a second civil war, which in
utility of the status quo. External support can change
turn will create another post-conflict environment
the expected utility of conflict by altering the probthat is ripe for renewed conflict. Collier et al. (2003) “This project rests on the fundamenability of victory, the payoffs of victory and defeat,
tal premise that cases of civil war
make a sound empirical case for the presence of the
and the bargaining leverage of the potential-comconflict trap—the best predictor of whether a country
recurrence are theoretically distinct batants. If foreign sponsorship is present, then there
will find itself in civil war next year is whether it is
is an increased probability that the sovereign authorfrom cases of first-time civil war
experiencing civil war now, and 44% of countries
ity of the state is not absolute and that rational
onset.”
experience a second civil war within five years of
combatants would be more likely to initiate war. If
the initial war’s termination.
there is an increased probability that the above two conditions are met, then
It has been argued that cases where there is adequate motivation for there is an increased probability that civil war recurs. This logic produces
civil war are fairly common (whether these motives are understood to be a “rival explanation” to the ODT-inspired theory I present. This rival
profit-driven, primordialist or of another variety is not relevant to the theory explanation holds that external military support of any type (no offense or
proposed here), and that the viability of civil war often functions as a suf- defense distinction) reduces the duration of peace and generates my first
ficient condition for civil war occurrence (Collier et al., 2003; Collier & hypothesis:
Hoeffler, 2004; Salehyan, 2009). The perspective of this project is that
focusing on the capacity for civil war—as opposed to the motivation for
H1: The presence of external military support is associated with a shorter
war—is the better way to theorize about civil war recurrence.1 We will peace duration.
proceed under that assumption that a recent civil war is a sufficient reason
H1 operates under the assumption that all types of external support
to assume the presence of adequate motivation for civil war. This means
that if civil war is not recurring, it is likely due to a lack of capacity to engage function to increase the probability of civil war recurrence. This, however,
in warfare. This project will argue that external military support plays a may not necessarily be that case. Prima facie, the idea that offensive forms
primary role in building combatants’ capacity for warfare, especially in of support encourage attacking, while defensive forms of support encourage
post-conflict countries where such capacity may have been greatly reduced entrenching seems to make sense.
Traditional ODT argues that technological innovation alters the superiin the previous war. By exclusively addressing possibilities for civil war
recurrence in post-conflict countries, this study also purposely chooses a ority of offensive or defensive technologies in the international system (Van
domain of cases in which the there is a higher probability of a security Evera, 1998). The theory proposed here argues that technological importadilemma existing among domestic actors. This universe of cases should be tion alters the availability of offensive and defensive technologies within a
highly sensitive to the availability of offensive and defensive military tech- nation. While the form of technological change (technological importation
and technological innovation), the effect of such change (availability and
nologies.
This project adopts the framework of Quinn, Mason and Gurses (2007) superiority), and the levels of analysis (domestic and international) each
with regard to the two necessary conditions for the recurrence of civil war: differ, the logic tying the theories together is nearly identical: increased
an opposition group must be capable of challenging the state’s claim to capacity for offense (changing the status quo) is likely to drive strategic
exclusive sovereign authority (dual sovereignty); and a potential combatant actors to initiate war in an attempt to alter the status quo in their favor;
group must be able to rationalize conflict re-ignition—the expected utility increased capacity for defense (preserving the status quo) is likely to drive
of war must be greater than the expected utility of peace for at least one
1 This study does not speculate on how useful its theoretical assumptions are for
theorizing about civil war onset.
30
2 While there are many other possible necessary conditions for civil war recurrence, my model focuses in on these two. Another possible necessary condition
comes from Walter (2004): individuals must be able to rationalize engaging in
rebellion—the expected utility of participating in rebellion must be greater than
the expected utility of supporting the state or inaction.
3 This distinction in ordering principles is barrowed from Waltz (1979).
The Hinckley Journal of Politics 2014
strategic actors to hunker down in an attempt to better protect what they dissatisfied, but incapable of affecting change, to attempt a revision of the
already have under current conditions.
status quo. Defensive types of support—those that increase the capacity
For each of the major differences between traditional ODT and my for protecting the status quo power relationships—should lead to a lower
theory (form of technological change, effect of technological change, and probability of war recurrence. Such status quo–entrenching capacity is
level of analysis), my alteration serves to increase the overall utility of the likely to make altering the status quo more difficult. Ambiguous types of
theory. The shift of the effect of technological change from superiority to support—those that increase the capacity for both offense and defense—
availability allows for a much clearer theory. When compared with supe- should not significantly impact peace duration. Ambiguous types of support
riority, availability is easier to operationalize, more constraining, and less are likely to contain countervailing tendencies (they are offensive in some
prone to misperception. Together, these features of availability sidestep ways, defensive in others). These countervailing tendencies are likely to
many of the criticisms of traditional ODT.4
result in the support not substantially altering the expected utility of war
The shift of the form of technological change from innovation to impor- relative to the expected utility of the status quo.5 The core logic of this
tation and the shift of the unit of analysis from the international system to argument is that when it is better to attack than defend in the short-run,
the nation-state both serve a similar purpose: to increase the number of instability is more probable than it would be if the inverse is true.
cases and the variation across those cases. By viewing each nation-state as
If this is the case, then H1 is not likely to be supported due to the opposits own technological environment that is subject to influence by the impor- ing effects of offensive and defensive types of support. However, the
tation of external technologies, we can dramatically increase the number following three-part hypothesis should be supported if offensive and defenof cases to test the predictions of the theory. Instead of merely examining sive forms of support have distinct impacts on recurrence:
one international system across time, we can analyze hundreds of national
H2A: The presence of offensive external military support is associated
systems across time. Not only does this offer a larger number and variety
of cases, but each of these cases is likely to have more variance in technol- with a shorter peace duration.
ogy over time.
H2B: The presence of defensive external military support is associated
In the international system, the most advanced technology available to
great powers progresses slowly over time, and once a technology becomes with a longer peace duration.
available, it rarely becomes unavailable until it becomes strategically obsoH2C: The presence of ambiguous external military support has no siglete. This is not necessarily true of national systems. A small, non-industrialized country, for example, would likely import the majority of its small nificant effect on peace duration.
arms, making the availability of small arms in this country sensitive to the
country’s external environment. Unlike the case of great powers in the If H2 is supported (and H1 is not supported), then there is strong support
international system, a non-obsolete technology (the small arms) may for the utility of conceptualizing types of external military support as
become unavailable at a certain point in time due to the lack of an external offensive or defensive. This could lead to theoretical speculation about how
sponsor state or the application of more stringent small arms non-prolif- these different types of support (offensive and defensive) are used by the
different types of actors that take part in a civil
eration measures. Such cases allow an analysis of what
war: states and rebel groups.
happens when a military technology is removed from
Traditional ODT treats all actors as like units
a strategic environment. While traditional ODT can
(symmetrically), since the only actors it addresses
only speculate on the effects of certain technologies “I propose that the symmetric
are states. My theory, however, is being applied to
by looking at the “before and after” of their initial
model is more useful in assessing
states
and rebel organizations. There are two
adoption (since from that point on, they are always
the effects of offensive and defenpotentially viable interpretations of how these two
available), the analysis offered in this paper can assess
sive technologies. My theory treats
actors should be conceptualized. The first potenthe impacts of technologies more thoroughly by
both states and rebels as rational
tial conceptualization is an asymmetric model:
looking at the fluctuating availability of a given techactors seeking to maximize their
states are defensively-oriented entities with a
nology across time for each national system.
“watch the throne” mentality, and rebel groups are
utility.”
Keeping these differences from traditional ODT
offensively-oriented entities with a “capture the
in mind, I now present the following explanation for
how the offensive or defensive nature of external military support will impact state” mentality. If the asymmetric model is adopted, then we should expect
the duration of peace in post-conflict countries: Offensive forms of support— states to value defensive support significantly more than offensive support,
those that increase the capacity for accomplishing revisionist goals—should while the opposite would be true for rebels. The second potential conceplead to a higher probability of war recurrence. Increased capacity for tualization is a symmetric model: once civil war breaks out, what was
changing the status quo is likely to drive actors who were previously formerly “the state” has ceased to possess a monopoly of the legitimate use
of force, and as thus ceased to be an effective state. If the symmetric model
is adopted, then we ought to view neither warring party as playing pure
defense or pure offense. In this model, there is no incumbent and no
4 Specifically, the use of availability avoids the following three criticisms leveled
challenger—merely two (or more) contenders.
at traditional, superiority-focuses ODT: superiority is a vague nation that is difI propose that the symmetric model is more useful in assessing the
ficult to measure or assess in practice; superiority is not particularly constraining—
effects
of offensive and defensive technologies. My theory treats both states
states are free to act against the incentives of the ODB; and superiority is highly
prone to misperception. Availability is simple to define—either a technology is
present at a specific place and time, or it is not. It is also highly constraining:
regardless of the motivation or incentives to act offensively, the unavailability of offensive military technologies would prevent an actor from taking offensive action.
Finally, availability is significantly less likely to be misperceived. This is largely a
product of how much easier availability is to define, but ought to be considered
separately because it addresses a unique criticism of traditional ODT.
5 Specific examples of what this study considers offensive, defensive and ambiguous support are provided in the research design.
31
Offense, Defense, and the Causes of Civil War Recurrence
and rebels as rational actors seeking to maximize their utility.6 Depending
on the strategic environment, states may be prompted to initiate war or
rebels may be prompted to entrench themselves and wait for a more opportune time to challenge the state.7 The following hypotheses ought to be
supported if the symmetric model is more accurate description of civil war
than the asymmetric model:
H3A: The presence of offensive external military support for the state is
associated with a shorter peace duration.
H3B: The presence of defensive external military support is for the state
is associated with a longer peace duration.
H3C: The presence of offensive external military support for rebel groups
is associated with a shorter peace duration.
H3D: The presence of defensive external military support for rebel groups
is associated with a longer peace duration.
This set of hypotheses is nearly identical to the first two parts of H2.
The core difference is that each claim is being tested separately for states
and rebels, allowing me to assess whether or not the two groups are similar
in their response to offensive and defensive technologies.
RESEARCH DESIGN
This section will discuss the plan to be implemented in testing the hypotheses presented above. Specifically this section will do the following: 1)
identify the universe of cases; 2) operationalize concepts central to the
hypotheses being tested; and 3) discuss the analytical technique utilized to
test the hypotheses.
Domain Identification
The temporal domain of the analysis is 1976 to 2009. This period has been
selected primarily to accommodate methodological restrictions: reliable
data on the types of foreign support considered in this study are only available for this period of time. The UCDP External Support Dataset contains
data from 1975 to 2011 (Högbladh, Pettersson, & Themnér, 2011). However,
my operationalization of support provision (discussed in the next section)
further limits my temporal domain by one year. While it would be preferable to consider all cases from 1945 to present, this domain is theoretically
appropriate since the late 20th century saw a drastic increase civil wars,
many of which were recurring conflicts. The spatial domain of this project
6 Here I return to referring to one actor as a state and another actor as the rebels,
despite showing above that under the symmetric model, this distinction is not
particularly accurate. I do this for conceptual clarity and brevity, as there is still
one entity which may colloquially be called “the state” and one which may be colloquially called “the challenger,” “the rebels,” or “the insurgents.”
7 For example, if a state finds itself in a clearly offensive environment, its most
strategic action could be to employ its offensive capabilities to repress or eliminate
dissatisfied constituencies before they have an opportunity to form an organized
rebellion. Taking such an offensive action may give the state a first-strike advantage, but if the repressed group is able to form an organized resistance, it also
embroils the state in a civil war that may have been avoided otherwise. On the
other hand, if a potential challenger finds itself in a clearly defensive environment,
its most strategic action could be to avoid conflict with the state, buying time until
the strategic environment favors offense. This way, the would-be rebels keep any
resources they have already accumulated and continue to exist as a political unit—
allowing them to live to fight another day.
32
Jordan Roberts
is global, encompassing all cases of civil war termination (and subsequent
post-war peace) in the temporal domain. Including all cases of civil war is
advantageous for the following reasons: 1) there is no theoretical expectation
that the dynamics of civil war recurrence are significantly different across
cultures or geographic regions; and 2) a global scope allows for this study
to draw more general conclusions about the effect of external military
support on peace duration. The unit of analysis for this project is the postwar country-year—each post-war year is treated as a potential year for war
recurrence.
Operationalization
The dependent variable in this project is civil war recurrence. For the purpose
of the analysis, civil war is operationalized as a higher threshold version of
what is referred to as “armed conflict” by the Uppsala Conflict Data Program
(UCDP): “a contested incompatibility that concerns government and/or
territory where the use of armed force between two parties, of which at least
one is the government of a state, result[s] in at least 25 battle-related deaths”
(Gleditsch et al., 2002). This project’s definition of civil war alters the UCDP
definition by raising the battle-related deaths threshold to from 25 to 1,000.
This was done in order to capture recurrences of major fighting.8 Battlerelated deaths data is retrieved from the UCDP PRIO Battle Deaths Dataset
1946–2008 (Lacina & Gleditsch, 2005).9 Furthermore, UCDP applied their
definition of armed conflict to specific conflict dyads, but this project simply
applies the high-threshold definition to a given country for a given year.10
In other words, for a conflict to be included in the dataset constructed for
this study, at least one year of the conflict must have 1,000 or more battlerelated deaths. The civil war lasts for as many years as the 1,000-battlerelated-deaths threshold is met.11 An exception is made if the battlerelated deaths count falls below 1,000 for only one year, in which case that
year is coded as a lull in the fighting, not a peace year. If the battle-related
deaths count falls below 1,000 for consecutive years, those years are coded
8 While this paper consistently refers to civil war as if it is a simple off-or-on
binary, “civil war” violence can vary across a wide spectrum in reality. The goal of
this study is not to evaluate when civil wars exist per se, but to evaluate when mass
violence associated with civil conflict exists. For example, if a country experiences intense civil war (1,000 or more battle-related deaths) for a number of years,
followed by minor armed conflict for an extended period (less than 1,000, but
more than 25, battle-related deaths), and then more intense civil war, the UCDP
operationalization results in observation of civil war for the entire period. UCDP’s
definition results in coding many wars that subsided (a couple years of intense
fighting, followed by many years of lower level conflict) as a decades-long civil
war, thus obscuring the recurrence of major fighting, which is what this project is
fundamentally seeking to understand.
9 This dataset contains three measurements for annual battle fatalities: the best
estimate, the low estimate, and the high estimate. For many conflict-years, a best
estimate could not be determined. I use the best estimate when available. When
the best estimate is missing, this project uses the average of the high and low
estimate. It is assumed that this value is closer to the true value than the extreme
high and low estimates.
10 As this project uses the unit of country-year (instead of conflict-year), the
battle-related deaths for concurrent conflicts are combined for a given year. For
example, if there are two conflicts in the same country during the same year, and
each conflict inflicts 500 casualties, that year is coded as a civil war year (since it
meets the 1,000-battle-deaths threshold).
11 There is one exception to this rule: the war between the United States and alQaeda. The increased casualty threshold and UCDP criteria are met for this case;
however, this conflict is fundamentally different from a civil war and encompasses
an international dynamic not present in other cases of war between a state and
non-state actor. Thus, this conflict was removed from the analysis.
The Hinckley Journal of Politics 2014
as peace years. If the battle-related death count for a given year meets the superiority of offense—commonly called the offense-defense balance.14
threshold after two or more peace years, then that year is coded as the start
This project uses a proxy for offensive support: “weapons support” in the
of a new civil war—a recur year. Due to methodological restrictions con- UCDP External Support Project—Primary Warring Party Dataset. Weapons
cerning my independent variables of interest (elaborated on below), initial support “includes donations, transfers, supplies or loans of weapons or
wars must end in 1975 or later for their recurrences to be acknowledged in ammunition of any kind” (Högbladh, Pettersson, & Themnér, 2011). This
my dataset.
category of support does not perfectly conform to the ideal-type of offensive
There are numerous independent variables of interest in this project. support, but it is the closest approximation for offensive support in the
The first is the existence of external military support. For this variable, the currently available data.
coding decisions made in the UCDP External Support Project—Primary
A proxy is also used for defensive support: “materiel/logistics support”
Warring Party Dataset are used for the creation of the variable “external_ in the UCDP External Support Project—Primary Warring Party Dataset.
exists,” which is a binary variable indicating the existence of “clearly estab- Materiel and logistical support includes many forms of non-weapon supplies.
lished external support” (Högbladh, Pettersson, & Themnér, 2011). A Examples include vehicles, field hospitals, construction bulldozers, troop
significant limitation of the external support data is that it only contains transportation, and repair and support facilities (Högbladh, Pettersson, &
observations for country-years containing a conflict that meets the UCDP Themnér, 2011). This category of support is too broad to be entirely defendefinition of armed conflict. While Högbladh, Pettersson, and Themnér sive, but is the closest to a purely defensive support type.
(2011) have observations for some years coded as peace years by this study
For this study, ambiguous support is also operationalized via proxy:
(those that meet the UCDP battle-related deaths threshold, but not the “funding/economic support” in the UCDP External Support Project—Primary
1,000-battle-related deaths threshold), many more years have missing Warring Party Dataset. Funding and economic support includes cash
observations. This project proxies the provision of support during these donations, military loans, and military grants, but does not include humanyears with the perceived availability of support.12 The perceived availabil- itarian, development or balance of payments aid/loans (Högbladh, Pettersity of support is estimated based on the most recent year for which an son, & Themnér, 2011). This category is the best proxy for ambiguous
observation is present. In other words, the value for the most recent support, since financial resources are the most fungible across offensive and
observation is imputed for the missing observations until the next observa- defensive military objectives.
tion containing a value of support occurs. This estimation is based on the
Numerous variables must be controlled in order to isolate the effect of
assumption that both rebels and states base their perceived ability to attract external support on civil war recurrence. First, gross domestic product per
external support on their ability to have attracted such support in the most capita (GDP per capita) is controlled by using the data from the Economic
recent year of conflict.
Statistics Branch of the United Nations Statistics Division (UNSD, 2012).
The remaining explanatory variables of interest used in this project are This variable is used to estimate the wealth of a country. Since a lack of
all sub-categories of existence of external support. All support variables wealth is associated with civil war, not including this control variable would
are present in three forms—general, rebel, and state. General support is bias the results of the analysis. Second, level of democracy is controlled for
present when either rebels or the state are supported; rebel support is present using the polity2 variable from the Polity IV Project (Marshall, Gurr &
when rebels are supported; state support is present when the state is sup- Jaggers, 2013). Since different levels of democracy have been associated
ported. In country-years containing conflict between a state and multiple with civil conflict, the exclusion of this control variable would result in
rebel groups, only one rebel group must receive support for that observation omitted variable bias.15 Third, the existence of a previous peace agreement
to be coded as having rebel support. This coding decision was made to at the conclusion of the most recent period of conflict is included as a control.
keep the interpretation of the “true” values for all dummy/binary variables Data for this variable was retrieved from the UCDP Conflict Termination
consistent. The UCDP External Support Project—Primary Warring Party Dataset (Kreutz, 2010). This variable is controlled because the presence of
Dataset simply codes for the presence or lack of presence of support (Hög- a peace agreement is thought to be negatively associated with the probabilbladh, Pettersson, & Themnér, 2011). Therefore, this study has simply coded ity of civil war recurrence. Fourth, since this project required consolidating
for the presence of support for any rebel group—this project does not take observations for concurrent conflicts, a control for multiple rebel groups
into account which or how many rebel groups receive the support.13
was used in the analysis. This variable was generated during the process of
Even with the switch from superiority to availability, operationalizing consolidating concurrent conflicts by country-year, and is controlled because
offensive and defense technologies is still a great challenge. Many scholars rebel disagreements, infighting, and collective action issues may affect their
acknowledge that distinctions will never be entirely clear and will always be ability to reignite war.
prone to misperception by political actors and scholars alike (Jervis, 1978;
Van Evera, 1998). That being said, I have operationalized both offensive and Analytical Technique
defensive technologies to the best of my abilities, given present data limitations.
It is worth repeating that I am operationalizing the availability of offensive Each model used in this project is a Cox proportional hazards model, which
technology and the availability of defensive technology, not the relative is utilized to measure the duration of peace. The hazard/failure used in the
models is civil war recurrence—the recur year. Each model includes identical control variables: lagged GDP per capita, lagged polity2, previous peace
agreement, and multiple rebel groups. The independent variable(s) of interest
12 While some may think that the transition from availability to perceived
availability reduces the explanatory power of my theory or moves it even farther
from traditional ODT, we should not forget the importance Van Evera places on
perceptions of the ODB: World War I is explained as a result of a misperceived
ODB (1998).
13 While this project does not take into account which or how many rebel
groups receive support, this is partially controlled for with the multiple rebel
groups variable—which will be discussed below.
14 For a discussion of potential operationalizations for the offense-defense balance, see Glaser and Kaufmann (1998). 15 Both GDP per capita and polity2 are lagged by one year in this project’s models, because economic and political conditions from the previous year are more
likely to affect civil war recurrence than similar observations for the year itself.
More concerning, observations for the year itself could be highly distorted by the
presence (or lack) of civil war, creating an endogeneity problem.
33
Offense, Defense, and the Causes of Civil War Recurrence
Jordan Roberts
differ depending on the hypothesis being tested, but in each case consists of
one or more types of support. For each model in the analyses, there were a
total of 520 observations. In order to test H1, a model using the existence
of foreign sponsorship and the aforementioned controls will be used.
For the test of H2, several models will be employed: three which include
each of the categories of support (offensive support, defensive support, and
ambiguous support) on their own; one that includes the two types of support
expected to have significant results (offensive support and defensive support);
and one that includes all three categories in the same model.
In order to test H3, two models will be used: a model including offensive
support for the state and defensive support for the state, and a model including offensive support for rebel groups and defensive support for rebel groups.
as is the case with Model 2E—ambiguous support remains insignificant, as
expected.18
RESULTS AND ANALYSIS
My analysis also revealed support for my secondary hypothesis: H3
(H3A: The presence of offensive external military support for the state is
associated with a shorter peace duration; H3B: The presence of defensive
external military support for the state is associated with a longer peace duration; H3C: The presence of offensive external military support for rebel groups
is associated with a shorter peace duration; H3B: The presence of defensive
external military support for rebel groups is associated with a longer peace
duration). Model 3A, which includes both offensive support for the state
and defensive support for the state supports H3A and H3B at the 95% and
the 99% confidence levels, respectively.
As expected, the analysis did not support the rival explanation’s hypothesis:
H1 (The presence of external military support is associated with a shorter
peace duration). Model 1A shows that the external military support variable
was not significant by any conventional standard. This is possible evidence
that general support has no clear effect on civil war recurrence. Further
evidence can be found in Model 1B (which finds external military support
for the state to be insignificant), Model 1C (which finds external military
support for rebel groups to be insignificant), and Model 1D (which finds
external military support for the state and external military support for rebel
groups insignificant when assessed together).16
However, the analysis did support my primary hypothesis: H2 (H2A:
The presence of offensive external military support is associated with a shorter
peace duration; H2B: The presence of defensive external military support is
associated with a longer peace duration; H2C: The presence of ambiguous
external military support has no significant effect on peace duration). Model
2A found that, when assessed independently, offensive support is insignificant. Model 2B found that, when assessed independently, defensive support
is significant at a 95% confidence level. Model 2C found that, when assessed
independently, ambiguous support is insignificant.17 While Model 2B
provides compelling results, Model 2D revealed a much more interesting
finding: that when both offensive support and defensive support are included in a model, both variables are highly significant, have the expected impact
on peace duration, and have large magnitudes. When paired together, both
offensive support and defensive support are significant at a 99% confidence
level—meaning that each form of support experiences increased significance
when the opposite form is controlled. Furthermore, the presence of offensive support increases the probability of civil war recurrence for a given
year by 680%, while the presence of defensive support decreases the probability of civil war recurrence for a given year by 93%. When ambiguous
support is included in a model with offensive support and defensive support—
Model 3B, which includes both offensive support for rebel groups and defensive support for rebel groups supports H3C and H3D at the 90% and the 95%
confidence levels, respectively. In sum, offensive and defensive support
have the same effects no matter who receives them: offensive technologies
always increase the probability of war; defensive technologies always decrease
the probability of war.
POLICY IMPLICATIONS AND AVENUES FOR FUTURE RESEARCH
These findings have uncovered a series of salient policy implications: the
types of support external actors provide can extend (or cut short) the dura-
16 See Appendix A for full results for Model 1B, Model 1C, and Model 1D.
17 See Appendix A for full results for Model 2A, Model 2B, and Model 2C.
34
18 See Appendix A for full results for Model 2E.
tion of peace in post-conflict countries. By providing defensively-oriented
support—such as field hospitals, construction equipment, and maintenance
of immobile defensive equipment—external parties can decrease the likelihood of war recurrence. By providing offensively-oriented support—even
to actors dedicated to protecting to status quo—external parties will increase
the probability of recurrence. Potential interveners thus cannot simply ask
if intervention should happen and whom they should support: they must
also ask how they ought to support them. Furthermore, many outside
parties try to foster stability by “propping-up” weak regimes with offensive
support to be used for repressing dissent before it can transform into rebellion. The analysis conducted in this study shows that providing such
offensive support is more likely to result in war than stability. There is still much to be done to improve our understanding of how
external military support impacts civil war recurrence. One of the clearest
limitations of this project is the lack of data on the availability of foreign
support during peace years. Collection of such data would allow for a more
precise analysis that does not rely on assuming that potential combatants
base their perceived ability to attract external military support on the support
provided during the most recent conflict year.
Additionally, the variety of support providers should be explored. This
project relied on data that only measured support from foreign states.
Diasporas, refugee camps, foreign rebel organizations, criminal organizations, and even wealthy individuals can also support combatants, and may
do so in fundamentally different ways than foreign states. Some categories
of sponsors may disproportionally provide offensive or defensive support,
which would have significant implications for the theory presented in this
study.
This paper set out to explore the effect of external military support on
peace duration, and has done so using a series of proportional hazards
models. This analysis has filled an important gap in the peace duration
literature by considering external support as a primary catalyst for recurrence and disaggregating external support into offensive and defensive
technologies. The results of testing the impact of offensive and defensive
support yielded both high magnitudes and significance: Not only do
different types of support matter a great deal, but this study provides robust
support for these findings. Furthermore, we have found new evidence in
support of the core logic of offense-defense theory. By exploring new testing
grounds and making useful alterations to the theory, this paper has extended ODT’s scope and significance.
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Offense, Defense, and the Causes of Civil War Recurrence
36
INTRODUCTION
Jordan Roberts
The Hinckley Journal of Politics 2014
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