Explaining the Severity of Civil Wars
Author(s): Bethany Lacina
Source: The Journal of Conflict Resolution, Vol. 50, No. 2 (Apr., 2006), pp. 276-289
Published by: Sage Publications, Inc.
Stable URL: https://www.jstor.org/stable/27638487
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Explaining the Severity of Civil Wars
BETHANY LACINA
Political Science Department
Stanford University
The burgeoning literature on civil conflicts seldom considers why some civil wars are so much deadlier
than others. This article investigates that question using a new data set of the number of combat deaths in
internal conflicts from 1946 to 2002. The first section presents descriptive statistics on battle deaths by era,
conflict type, and region. The article then tests state strength, regime type, and cultural characteristics as pre
dictors of the number of combat deaths in civil war. The determinants of conflict severity seem to be quite
different from those for conflict onset. Democracy, rather than economic development or state military
strength, is most strongly correlated with fewer deaths; wars have also been less deadly on average since the
end of the cold war. Religious heterogeneity does not explain the military severity of internal violence, and
surprisingly, ethnic homogeneity may be related to more deadly conflicts.
Keywords: civil war; battle deaths; democracy; state strength; ethnic violence
v^ivil conflict is the most common form of warfare, accounting for all but three of the
wars that broke out from 1990 to 2002{ and 90 percent of civilian and combatant battle
deaths during the same period.2 As greater academic attention has been paid to internal
warfare, scholars concentrating on large-/? statistical work have begun to converge on a
handful of factors that seem most important in explaining civil conflict onset and dura
tion (for reviews of the quantitative literature, see Lacina 2004; Sambanis 2002,2004).
But wars come in different sizes, ranging from brief conflagrations that kill relatively
few, to geographically isolated but prolonged insurgencies, to enormous military con
tests sweeping across entire states. The number of deaths in these conflicts varies from
the widely used threshold of 1,000 killed to the far more massive toll of the three
1. According to the Uppsala/PRIO list of state-based armed conflicts. SeeGleditschetal. (2002) and
Eriksson, Wallensteen, and Sollenberg (2003).
2. Calculated from Lacina and Gleditsch (2005).
AUTHOR'S NOTE: Sincere thanks are due to Jim Fearon, Nils Petter Gleditsch, and Scott Gates for help
throughout this project. My Stanford colleagues will also notice how much I owe to their insights. Earlier
versions of this article were presented at the 2004 Joint Session of Workshops of the European Consortium of
Political Research, in Uppsala, Sweden, and the 2005 Annual Meeting of the International Studies Associa
tion in Honolulu. The project benefited from financial support by the Centre for the Study of Civil War at the
International Peace Research Institute, Oslo, where I began work on this project and remain an affiliated
researcher. Replication data and the appendix are available at http://jcr.sagepub.eom/cgi/content/full/50/2/
276/DC1/ and are posted with the Lacina and Gleditsch (2005) battle deaths data at http://www.prio.no/
cscw/cross/battledeaths.
JOURNAL OF CONFLICT RESOLUTION, Vol. 50 No. 2, April 2006 276-289
DOI: 10.1177/0022002705284828
? 2006 Sage Publications
276
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Lacina / EXPLAINING THE SEVERITY OF CIVIL WARS 277
largest internal wars of the post-World War II era?in Vietnam, China, and Afghani
stan?which combined to destroy more than 3 million people in combat. Yet, to date,
academic work has focused on the incidence of civil war rather than accounting for
this variation in severity.
Knowing why some conflicts tend to be more deadly than others is a question of
inherent interest. The legacies of internal violence are poverty (Bayer and Rupert
2004; Collier et al. 2003; Murdoch and Sandier 2002) and poor public health (Gho
barah, Huth, and Russett 2003; Krug et al. 2002). In 2000, seven of the ten countries
with the worst mortality rates among children younger than age five had recently suf
fered a civil war (Black, Morris, and Bryce 2003). And the depth of these impacts is
likely in part determined by the severity of the conflict that has taken place. More
deadly conflicts may also be more likely to recur (Fortna 2004).
Do wars generate high numbers of battle deaths when widespread grievances trans
form a marginal insurgency into a mass movement? Are political institutions tied to
conflict size? Or is the opportunity to rebel against a disorganized and poor state suffi
cient to cause large numbers of battle deaths, even if the insurgents are a small group?
These questions parallel the debate found in studies of conflict onset, some of which
stress the importance of factors that provide resources and pecuniary incentives for
rebellion (Collier and Hoeffler 2001) or the opportunities for insurgency offered by a
weak state (Fearon and Laitin 2003), while others argue for the importance of ethnic or
religious factors, political repression, or regime type (Elbadawi and Sambanis 2002;
Ellingsen 2000; Hegre et al. 2001; Reynal-Querol 2002).
This article presents data on battle deaths in civil conflicts worldwide from 1946 to
2002, providing both a descriptive account of these data and a test for correlates of
severity among civil wars. The first section discusses the use of battle deaths as a mea
surement of the severity of civil conflict and presents new combat deaths data on civil
conflicts from 1946 to 2002. Second, I propose a series of hypotheses on possible
determinants of the severity of civil conflict. Finally, regression analysis is used to
identify factors that explain the variation in civil war battle deaths. In contrast to most
analyses of civil war onset and duration, political variables outperform measures of
state strength in predicting battle violence.
CONFLICT SEVERITY AND BATTLE DEATHS DATA
Gauging the "size" or "severity" of civil wars is by no means straightforward. A
number of factors could be relevant to determining whether one civil war was more
devastating than another: how many people and resources were devoted to fighting in
the conflict, the geographic range of violence, and the indirect and direct losses due to
the war, in both human and economic terms. There is a dearth of theory on how to esti
mate the full impact of war and an even more serious lack of cross-national informa
tion about these losses (Lacina and Gleditsch 2005). But it is possible to compare the
military severity of civil conflicts based on battle deaths, meaning combatants and
civilians killed by means of violence in the course of a military contest. Such fatalities
can be distinguished from indirect deaths caused by war-related hardships, as well as
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278 JOURNAL OF CONFLICT RESOLUTION
o
500000 1000000 1500000
Total Battle Deaths
-1
2000000
Figure 1 : Histogram of Total Battle Deaths in Civil War, 1946-2002
from deaths in unorganized violence (such as rioting) or in one-sided violence (such as
genocide). A focus on battle deaths would not necessarily be a useful way to determine
which wars have had the greatest humanitarian cost, but it is a reasonable measure of
the scale of combat.
I explore civil conflict severity here with a new data set of battle fatalities (Lacina
and Gleditsch 2005) based on incidents in the Uppsala/PRIO list of state-based armed
conflicts (Eriksson, Wallensteen, and Sollenberg 2003; Gleditsch et al. 2002). I com
piled the Lacina and Gleditsch (2005) fatalities data into estimates of total battle
deaths in 114 civil wars that took place between 1946 and 2002 in which at least 900
persons were killed.3
Perhaps the most notable feature of these data is the enormous skew in the number
of battle deaths caused in various civil wars over the past half century (see Figure 1).
The battle toll of civil wars clusters toward the low end of a range that runs from 900 to
more than 2 million in Vietnam. The median civil war in these data killed a total of
about 10,500 in combat (less than 0.5 percent of the maximum), while the average
number killed is almost six times that figure. Conflict fatality data also reveal signifi
3. The appendix to this article lists the civil conflicts used and the number of battle deaths recorded in
each. It is available online with the replication data for this article. See Lacina and Gleditsch (2005) for a full
description of the battle deaths data set used here, a complete definition of battle deaths, and a discussion of
the differing explanatory power of various measures of the human costs of conflict.
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Lacina / EXPLAINING THE SEVERITY OF CIVIL WARS 2 79
TABLE 1
Civil War Battle Deaths, 1946-2002,
Median Estimates by Era, Conflict Type, and Region
Category
Total
Battle Deaths
Rate of
Battle Deaths
Deaths per
100,000 People
Population of
Country in War
(Millions)
Role of cold war
Wars begun prior to 1989 18,000 2,700
Wars begun in 1989 or later 4,300 1,350
Conflict type
Nonsecessionist conflict 10,000 2,000
Secessionist conflict 9,100 2,300
Region
Sub-Saharan Africa 15,000 2,000
Americas 4,500 2,000
Central and South Asia 3,600 1,600
East and Southeast Asia and Oceania 24,000 2,400
Europe 8,800 4,700
Middle East and North Africa 15,000 2,800
130
35
140
26
130
160
14
39
31
170
17
15
67
9
4
47
57
23
cant variation by era, conflict type, and region4 (see Table 1). Post-cold war conflicts
have tended to be less deadly in terms of absolute numbers killed, rate of deaths, and
deaths normalized by population than cold war conflicts. Secessionist conflicts have
not been much less deadly in absolute terms or in deaths per year than nonsecessionist
conflicts, contradicting the assumption that because such wars are geographically iso
lated, they tend to be small.5 But wars of secession do seem to induce far fewer deaths
per capita than other conflicts, despite a similar annual rate of fatalities, because sepa
ratist conflict seems to occur primarily in large countries?the median population of a
country in secessionist conflict is almost eight times that of a country in a nonseparatist
civil war. Larger countries are probably more likely to have enclaves that are ethnically
or lingually distinct from the group controlling the capital and have the economic
potential to be viable states.
By geographic region, conflicts in East and Southeast Asia killed the most people in
combat, while wars in America, Europe, and Central and South Asia have had the
smallest battle death tolls. Europe's wars are the only ones to stand out in terms of rate
of fatalities, tending to kill relatively quickly; in fact, there have been only seven civil
wars in Europe since 1946, and only one (in Northern Ireland) lasted for more than
four years. Normalization by population size yields figures that are largest in the small
states of the Americas, as well as in the Middle East and sub-Saharan Africa, while
deaths in East and Southeast Asia, Central and South Asia, and Europe are signifi
cantly discounted. The r??valuation by population size is quite dramatic in some cases:
4. For a definition of the regions used, see Lacina and Gleditsch (2005).
5. Secessionist conflict was defined following the Uppsala/PRIO data set (Eriksson, Wallensteen,
and Sollenberg 2003).
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280 JOURNAL OF CONFLICT RESOLUTION
the absolute number killed in the median conflict in Central and South Asia is 80 per
cent of the similar figure for the Americas, but the Asian death rate per person is just 9
percent of the American rate. I will return to the relationship between battle deaths,
conflict duration, and total population in the regression analysis below.
WHAT DETERMINES CONFLICT SEVERITY?
Scholars of civil conflict onset have engaged in a debate over whether variables
relating to the opportunity to fight or the motivation to fight are most important to
understanding where civil war will occur. The severity of military conflict should also
relate to both opportunity and impetus, tending to be more deadly as the sides become
better armed and organized and as they become increasingly convinced that military
activity is their best strategy for obtaining their goals. Current civil war literature sug
gests that state capacity, regime type, and ethnic and religious diversity may determine
ability or willingness to initiate a civil conflict. By contrast, I discuss the potential of
each of these variables to predict conflict severity.
It is important to keep in mind that the question being investigated is what explains
the variation in the numbers of battle deaths among observed civil wars. In other
words, conditional on suffering a civil war, how deadly is combat likely to be? Factors
that make a country high risk for civil war may not have much predictive power for
explaining variation in deaths among civil wars. For example, if countries that fall into
internal conflict are generally poor, it may be that poverty is too ubiquitous to explain
much about which of these wars become most deadly. This study thus complements,
rather than replaces, work on civil conflict onset.6
STATE STRENGTH
Models for the onset of civil war have found that war is most likely to occur in
impoverished states. Fearon and Laitin (2003) have argued that low gross domestic
product (GDP) per capita is a strong predictor of civil war because it proxies for state
incapacity, while Collier and Hoeffler (2001) emphasize factors they believe
strengthen the states' challengers, such as large numbers of unemployed young men,
unregulated markets, lootable resources, and porous borders. A corollary hypothesis
might be that state capacity, which is associated with strong counterinsurgency, gen
eral institutional strength, and high opportunity costs to rebellion, explains which
states will have the smallest civil wars:
Hypothesis 1A: Among states experiencing civil conflicts, more severe conflicts will occur
in weak states.
6. It would be incorrect to use the results presented here to make predictions about how many civil
war combat deaths are likely to occur in a country selected at random, without first taking into account the
selection process that determines whether that state s likely to fall into civil war at all. However, I am not
convinced that a selection effects model for civil coni let severity is more useful than estimating conditional
probabilities, as random assignment of the "treatment ' of civil war is not just unobservable but conceptually
meaningless.
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Lacina / EXPLAINING THE SEVERITY OF CIVIL WARS 281
But while a weak state and aids to rebellion may make a war easy to start, they do
not necessarily determine how deadly the conflict will be, at least not in a straightfor
ward manner. On one hand, strong states are certainly less likely than weak states to be
faced with well-matched opponents, suggesting that weak states may have more trou
ble containing internal violence. On the other hand, civil conflicts in very weak states
and very poor societies are likely to feature militaries with limited organizational
capacity and limited access to technologies such as aircraft, tanks, and heavy artillery.
A small insurgent movement and a weak state may be in a stalemated civil war simply
because neither is able to seriously challenge the other's strongholds. And in wars of
outright state collapse, which Kalyvas (2005, 88) aptly characterizes as "symmetric
non-conventional" warfare, all combatant groups have minimal military strength and
organizational coherence. The resulting anarchic and disorganized conflict is typified
more by humanitarian crisis, predatory violence, and warlordism than sustained com
bat (Herbst 2004; Mueller 2003). Thus, there may not be any unidirectional relation
ship between weak states and severe civil wars:
Hypothesis IB: Among states experiencing civil conflicts, the severity of civil conflicts will
be uncorrelated with state strength.
A nonrelationship would be particularly plausible if the military capacity of both
the regime and its challengers is determined less by domestic economics than by out
siders' economic and military support. When foreigners support parties that would not
otherwise be able to sustain a military challenge or undertake competitive sponsorship
of different sides of a civil conflict, internal wars are likely to be more severe. Regan
(2000) has found that while external, military intervention in civil war may sometimes
create an overwhelming advantage on one side and end the war, in general, outside
participation on either or both sides of a conflict prolongs fighting. Thus, the following
can be predicted:
Hypothesis 1C: Among states experiencing civil conflicts, more severe conflicts will occur
when there is external military assistance to the government and/or its challengers.
Finally, the literature on state capacity and civil war onset calls attention to the
importance of geography to counterinsurgency. Fearon and Laitin (2003, 80) argue
that rough terrain aggravates state weakness because of the expensive infrastructure
investment necessary to control thinly populated territories, the easy cover it offers
insurgents, and the ease of monitoring the sparse population. Statistical analysis does
find a correlation between rough terrain, low population density, and conflict onset
(Collier and Hoeffler 2001; Fearon and Laitin 2003).
In predicting civil war battle deaths, however, it may be less important to note that
terrain can create the possibility for conflict and more important to note how terrain is
likely to affect combat tactics. In rough terrain, both sides will probably be forced to
deploy in relatively small units, reducing the number of people involved per engage
ment. Conflicts that feature large numbers of battle deaths usually include at least
some battles in urban and open territories where large numbers and heavy weaponry
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282 JOURNAL OF CONFLICT RESOLUTION
can be deployed, soldiers can be targeted with aerial strikes and artillery bombard
ment, and civilians are caught in the crossfire. It is probable that, conditional on being
able to launch an insurgency, wars fought in densely populated areas and through con
ventional battle methods are the most deadly. Thus, the relationship between terrain
and conflict severity seems likely to be the reverse of that between terrain and conflict
onset:
Hypothesis ID: Among states experiencing civil conflicts, less severe conflicts will occur in
states with rougher terrain.
REGIME TYPE
The severity of civil war may also be related to political considerations that influ
ence willingness to continue, escalate, and deescalate fighting. Thus far, there is only
mixed evidence of a role for regime type in conflict onset7 but some indication of a
relationship to conflict severity. Carey (2005) finds that the presence of executive con
straints, open executive recruitment, and breadth of political participation are all nega
tively associated with the probability of civil conflict escalation and the onset of large
civil wars, although they seem to make no difference in the likelihood of minor civil
conflicts.
There are at least three possible reasons to expect that regime type might relate to
combat severity, even if it does not relate to conflict onset. These are selection effects,
democratic norms, and the political adaptability of institutions. I consider the last to be
the most plausible link between regime type and conflict severity, although this study
cannot distinguish among the explanations in its empirical tests.
Selection effects play a major role in the literature on regime type and interstate
war. Democracies tend to win interstate wars, and it has been argued that this is in part
due to their tendency to pick fights they can win and minimize casualties to avoid pub
lic backlash (Bennett and Stam 1996, 243; Bueno de Mesquita and Lalman 1992,153
4; Siverson 1995). Democratic leaders, likely under public pressure to avoid blood
shed at home as well as abroad, may tend to grant concessions when faced with a
severe insurgent threat. As a result, one may observe only rather small, easily con
trolled insurgencies in states with publicly accountable leaders.
A second, normative perspective would argue that regime type influences conflict
severity because democratic governments are unwilling to use the harshest measures
against rebels or to inflict great collateral loss of life among civilians. Democratic
leaders may be constrained due to norm internalization, through institutional checks
on their powers (such as courts to prosecute cases of war crimes), or public pressure
arising from sympathy with insurgents or bystanders. Valentino, Huth, and Balch
Lindsay (2004) argue that democratic governments are less likely to resort to mass
7. Collier and Hoeffler (2001) and Fearon and Laitin (2003) find that economic measures trump
democracy in explaining conflict outbreak. But Elbadawi and Sambanis (2002) find that democracy, espe
cially several years of democracy, is negatively associated with the prevalence (onset and duration) of con
flict. Benson and Kugler (1998, 199) emphasize the immunity from conflict of democracies that are also
strong states.
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Lacina / EXPLAINING THE SEVERITY OF CIVIL WARS 283
killings of the civilian supporters of elusive guerillas. Democracy is also negatively
associated with the incidence of genocide (Harff 2003).
The third possible link between regime type and conflict severity is the possibility
that democracies are better equipped to co-opt, contain, and negotiate with rebels than
are other governments. Democracies have structures of government that allow for
power rotation and public participation in policy formation and provide for checks on
the center, such as an independent judiciary or federalism. These institutions are avail
able to incorporate insurgents as additional players in a peaceful political contest. For
example, India has dealt with internal insurgencies by developing a looser federalism
among its states (Brass 1994). The threat of post-World War II communist insurgency
in European countries such as Italy dissipated as far-left factions became incorporated
in the electoral process.
Note that the responsiveness of a democratic political system does not necessarily
guarantee that civil conflict will not break out?if concessions can be won through
insurgency, there remains an incentive to launch violent acts?but only that civil con
flict will be more readily contained. In fact, there may be greater incentives to launch
small insurgencies in democracies if such governments are both more sensitive to
political pressure to end internal disorder and have available institutions that make
concessions less costly compared to similar adaptations in an autocracy. By contrast,
in nondemocracies, challengers may assume that their best hope of achieving their
goals is military victory or the collapse of the current regime and accordingly choose
more deadly tactics (Lacina 2005).8
Combining the arguments regarding selection effects, norms, and institutional
adaptability yields the following hypothesis:9
Hypothesis 2: Among states experiencing civil conflicts, less severe conflicts will occur in
democracies.
THE ROLE OF ETHNICITY AND RELIGION
The third and final set of possible determinants of the combat severity of civil wars
are cultural characteristics that may cement the willingness to bear the costs of con
flict. Ascriptive identities, especially ethnolinguistic and religious loyalities, are often
suggested to be less flexible than political ideologies (Horowitz 1985; Huntington
1997; Thies 2004), leading some to contrast relatively civilized ideological warfare to
bloody, primordial ethnic conflicts (Duffield 1998; Kaldor 1999; Snow 1996; Thies
2004). If ethnic or religious conflicts are grounded in particularly strong antipathy or
are inherently zero sum in nature, it may be impossible for the parties to ratchet down
8. Some violent groups operating in democracies, such as the Euskadi Ta Askatasuna (ETA) in Spain
or the Orange Volunteers in Northern Ireland, have been known to alert the authorities prior to attacks so that
few or no casualties are inflicted (Pape 2003, 345). It is difficult to imagine this tactic, which is essentially
about political communication, being effective in the absence of a free press or against a regime that was not
publicly accountable for law and order.
9. Some studies of conflict onset stress regime stability over regime type (Hegre et al. 2001). A vari
able for anocracy (regimes falling between -6 and 6 on the combined Polity index) is not a significant corre
late of conflict severity when it is added to the models presented here.
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284 JOURNAL OF CONFLICT RESOLUTION
violence in favor of cohabitation. These dynamics are particularly likely to result in
severe combat if each antagonistic group comprises a substantial population, suggest
ing the following hypotheses:10
Hypothesis 3A: Among states experiencing civil conflicts, more severe conflicts will occur
in states that are ethnically polarized.
Hypothesis 3B: Among states experiencing civil conflicts, more severe conflicts will occur
in states that are religiously polarized.
On the other hand, the search for a statistical relationship between cultural factors
and conflict onset has uncovered only mixed results, and it would be quite surprising if
ethnic and religious hatreds made civil wars especially vicious without also making
them more likely.11 Also, despite the recent attention paid to it, ethnic conflict is nei
ther a new phenomenon (Kalyvas 2001) nor uniquely bloody. The Vietnamese and
Chinese civil wars, the largest of the post-World War II era, were primarily "ideologi
cal" in nature. Many civil conflicts with an ethnic dimension?for example, in
Afghanistan, Ethiopia, and Mozambique?escalated due to external military assis
tance provided in the name of cold war ideological schisms. And although cultural
demands are generally thought to be exceptionally rigid, any struggle for political
power can be zero sum if the players are sufficiently intractable. Regionally based cul
tural elites may be ready to accept power devolution and partial autonomy arrange
ments; competition for control of the center seems to admit, if anything, less chance
for compromise (Walter 1997).
MODELING CONFLICT SEVERITY
I now turn to an empirical test of the three groups of variables discussed?state
power, regime type, and cultural diversity?as determinants of the number of battle
deaths in civil conflicts between 1946 and 2002. The dependent variable is the severity
of battle violence in a civil conflict, measured as the natural log of total battle deaths.
The regression controls for variation in conflict duration and population by using the
log of each as independent variables.12
The first variable chosen to measure state capacity is military quality, the best avail
able indicator of counterinsurgency capabilities. Military quality is defined as military
10. Recall that one-sided violence is not included in battle deaths. Certain types of one-sided violence,
especially genocide, may be more closely related to cultural identity than are battle deaths. For a discussion
of determinants of massacres and other one-sided violence, see Harff and Gurr (1988), Harff (2003), and
Valentino, Huth, and Balch-Lindsay (2004).
11. Collier and Hoeffler (2001 ) and Fearon and Laitin (2003) find that ethnicity and religion do not
explain war outbreak, while Hegre et al. (2001 ) and Elbadawi and Sambanis (2002) report that ethnic hetero
geneity correlates with civil war. Ellingsen (2000) considers ethnic, religious, and linguistic identities simul
taneously and finds higher conflict risk in diverse nations.
12. In the case of ongoing conflicts, duration refers only to the number of years for which battle deaths
information was collected. The Lacina and Gleditsch (2005) fatalities data include low and high estimates of
battle deaths as well as best estimates, which are used here. My results are similar to those reported when I
use the low and high estimates. See replication data for details.
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Lacina / EXPLAINING THE SEVERITY OF CIVIL WARS 285
expenditure divided by number of military personnel (following Bennett and Stam
1996).13 The variable is log transformed and lagged by a single year. Therefore, these
figures may reflect the regime's accurate forebodings of conflict but not any upsurge in
spending or recruitment after the outbreak of war. I also test GDP per capita, adjusted
for purchasing power and for inflation, logged, and measured in the year prior to fight
ing. 14 GDP per capita is the most common proxy for state strength in the civil war liter
ature and seems to predict conflict onset consistently (Sambanis 2004).
I have suggested that domestic capacities may be less important than external mili
tary intervention in determining the severity of civil conflict. I test this hypothesis with
a dummy variable for wars beginning during the cold war, when there was a greater
availability of military assistance to states and rebel groups (Karp 1988; also compare
SIPRI 1969, 1978, 1988).15 As a final variable in the investigation of state strength, I
test the role of rough terrain by noting the log of the percentage of mountainous terrain
in the country.16
Turning to regime characteristics, I code a dummy variable for democracy, defined
as a score of 6 or higher on a combined Polity scale of regime type (Marshall and
Jaggers 2003).1V Finally, I note ethnic and religious polarization dummy variables,
coded as 1 where an ethnic or religious minority compromised at least 8 percent of the
total population.18
FINDINGS
Table 2 shows the results of ordinary least squares (OLS) regressions for battle
deaths in civil conflicts. Model 1 presents the regression of total battle deaths, and
model 2 is a trimmed specification using only variables significant in the first regres
sion; there are no missing observations for this model. Not surprisingly, the total num
ber of battle deaths increases as a function of time in conflict.19 However, a larger pop
ulation does not predict a higher number of deaths. The nonrelationship between total
13. Inflation-adjusted data on military spending and data on numbers of military personnel are from
the Correlates of War National Militaries Capabilities data set, version 3.01 (Singer, Bremer, and Stuckey
1972), and were downloaded with EUGene (Bennett and Stam 2000).
14. Data are from Fearon and Laitin (2003) and World Bank (2003).
15. The cold war dummy variable is coded for wars starting prior to 1989, following Collier and
Hoeffler (2001). The dummy succeeds in capturing some variation in the incidence of foreign military inter
vention, which featured in 61 percent of conflicts that began before 1989 and just 45 percent of those begin
ning after that time (calculated from replication data for Regan 2000). War-specific data on the incidence of
foreign military activity do predict more severe internal conflicts, but problems of endogeneity mean that it is
unclear whether this result is due to interventions being a cause of severe conflict or a response to it.
16. From Fearon and Laitin (2003).
17. The Polity scale gives regimes scores from 0 to 10 in terms of both democratic and autocratic char
acteristics. Changing the sign on the autocracy scores and adding the two scores places states along a range
from-10 to 10.
18. This coding rule follows Fearon and Laitin (2003). I also tested Fearon and Laitin's measures of
ethnic and religious fractionalization, defined as the probability that two members of a population are of the
same ethnicity or confession. They were not significant predictors of civil conflict severity.
19. Perhaps more interesting is that there is no statistically significant relationship between deaths per
year and conflict duration. A faster death rate does not seem to generate a countervailing tendency toward
shorter conflict. Thus, factors that predict large numbers of deaths should also predict high rates of death.
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286 JOURNAL OF CONFLICT RESOLUTION
TABLE 2
Ordinary Least Squares (OLS) Regressions of
Battle Deaths in Civil Conflicts, 1946-2002
Independent Variable
OLS Regression of In Total Battle Deaths
Coefficient (SE) p-Value
Model Ia
In Duration 0.81
In Population -0.044
In Military quality 0.10
In Gross domestic product -0.19
Cold war 0.67
In Percentage mountainous territory 0.10
Democracy -0.87
Ethnic polarization -0.98
Religious polarization 0.12
Intercept 9.50
Model 2b
In Duration 0.86
Cold war 0.59
Democracy -0.91
Ethnic polarization -1.00
Intercept 8.60
(0.12)
(0.081)
(0.12)
(0.18)
(0.31)
(0.12)
(0.36)
(0.34)
(0.32)
(2.00)
(0.11)
(0.27)
(0.33)
(0.30)
(0.35)
.000
.580
.400
.280
.036
.400
.017
.005
.710
.000
.000
.030
.006
.001
.000
a. n = 105. Adjusted R2 = 0.40.
b. n= 114. Adjusted/?2 = 0.43.
deaths and total population means that normalizing deaths by population may too
heavily discount deaths in large countries, as war does not seem to scale up in populous
nations.
Variables proxying state and rebel strength have no predictive power in these mod
els. Military quality has an unexpected positive sign and is not significant. GDP per
capita has the expected negative sign but is also insignificant. These results are
unlikely to be due to multicollinearity as an F test easily rejects the joint significance of
military quality and GDP per capita.20 The results here suggest that because state
capacity has contradictory significance for the likelihood of parity between combat
ants and their military capacity, it is difficult to find a correlation between state capac
ity and conflict severity.21 Terrain also has no explanatory power.
What seems to be more important for determining the military severity of a civil
war is the availability of foreign aid and intervention. The dummy variable for the cold
war predicts civil wars with about 1.8 times the number of battle deaths of later civil
conflicts.
20. An F test comparing model 2 to a similar specification, including gross domestic product/capita
and military quality, returns a test statistic of 0.62 (p-value = 54 percent).
21. A recentered quadratic term for military quality or gross domestic product/capita returns no evi
dence of a simple curvilinear function.
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Lacina / EXPLAINING THE SEVERITY OF CIVIL WARS 287
Political characteristics also strikingly outperform state power variables. More
democratic regimes are associated with smaller civil conflicts. The substantive effect
is even larger than that of the cold war, as civil wars in democracies are expected to
have less than half the battle deaths seen in conflicts in nondemocracies.
Finally, there are mixed results for variables measuring the cultural makeup of the
state. Religious diversity displays no significant correlation with conflict size. Inter
estingly, there is a significant and large negative coefficient on the variable for ethnic
polarization.22 The results were unexpected, but a post hoc explanation might be that in
ethnically homogeneous societies virtually the entire population can be implicated in
the conflict, and it is more difficult to determine who is on what side, leading to more
indiscriminate use of force. What is clear is that there is no indication in these results
that cultural diversity provides elites with remarkable advantages in mobilizing their
followers and convincing them to bear the costs of war, nor is there support here for a
thesis of bloody ethnic wars as opposed to civilized ideological wars, a distinction that
has always been tenuous at best.
CONCLUSION
It has been argued that grievances are so common across all societies that it is
opportunity?weak states and aids to rebellion?that determines where and when
wars begin. This may seem to suggest that political factors have little to contribute to
civil peace and that investment in counterinsurgency is the only road to stability. This
article has introduced a cautionary note against such a conclusion by pointing out that
knowing why wars start does not necessarily reveal when they will be most
devastating.
In the statistical work presented here, state strength variables do not explain why
some civil wars kill more people in combat than others. Nor does ethnic or religious
heterogeneity explain the severity of internal war. Instead, there is an unexpected link
between ethnic homogeneity and large wars. A strong predictor that a civil war will be
severe is the availability of foreign assistance to the combatants. Democracy is also
associated with fewer battle deaths; selection of conflicts, democratic norms, and
institutional adaptability may all play a role in explaining this finding. Further research
should focus on both testing the robustness of the relationship between regime type
and conflict severity found here and developing a more precise theory of how chal
lengers choose tactics against liberal and illiberal political regimes and how such
governments tend to respond to political violence.
22. The result in model 2 is not overturned even after exclusion of outliers from quite homogeneous
East Asian countries?namely, the Vietnam War, the Chinese Civil War, and the Cambodian Civil War from
1967 to 1975.
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288 JOURNAL OF CONFLICT RESOLUTION
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