Assessing the International Criminal Court

One of the most important issues surrounding international courts is whether they can further the dual causes of peace and justice. None has been more ambitious in this regard than the International Criminal Court (ICC). And yet the ICC has been the object of a good deal of criticism. Some people claim it has been an expensive use of resources that might have been directed to other purposes. Others claim that its accomplishments are meager because it has managed to try and convict so few people. And many commentators and researchers claim that the Court faces an inherent tension between the dual objectives of securing the peace and ending impunity for perpetrators of some of the most egregious crimes, including genocide, crimes against humanity, war crimes, and crimes of aggression. 
 
This chapter assesses the ability of the ICC to deter. In so doing, we follow the lead of the introduction and think not only about the Court’s performance in the narrow sense (e.g., how many people have been tried?) but rather think about the ways in which the ICC has contributed to a broader culture that refuses to tolerate impunity for violations of international criminal law. Because we must limit our topic to manageable proportions (and because we are social scientists and not lawyers) our focus is primarily on outcome performance rather than procedural performance. We focus on two outcomes alluded to in the introductory chapter: 1) reaching desired goals, and 2) deterring atrocities against civilians.

One of the most important issues surrounding international courts is whether they can further the dual causes of peace and justice. None has been more ambitious in this regard than the International Criminal Court (ICC). And yet the ICC has been the object of a good deal of criticism. Some people claim it has been an expensive use of resources that might have been directed to other purposes. Others claim that its accomplishments are meager because it has managed to try and convict so few people. And many commentators and researchers claim that the Court faces an inherent tension between the dual objectives of securing the peace and ending impunity for perpetrators of some of the most egregious crimes, including genocide, crimes against humanity, war crimes, and crimes of aggression. 2 This chapter assesses the ability of the ICC to deter. In so doing, we follow the lead of the introduction and think not only about the Court's performance in the narrow sense (e.g., how many people have been tried?) but rather think about the ways in which the ICC has contributed to a broader culture that refuses to tolerate impunity for violations of international criminal law.
Because we must limit our topic to manageable proportions (and because we are social scientists and not lawyers) our focus is primarily on outcome performance rather than procedural performance. We focus on two outcomes alluded to in the introductory chapter: 1) reaching desired goals, and 2) deterring atrocities against civilians.
As a criminal court, the ICC is much different than courts that settle disputes between states or disputes between private parties (e.g., investors) and states. The ICC fits four out of five of the criteria set out in the introduction. It decides issues of guilt or innocence on the basis of international law (greatly influenced in this case by domestic criminal procedures); it follows pre-determined rules of procedure, detailed in the Rome Statute, its founding document; the Court issues legally binding decisions and is composed of independent judges. States are parties to the Rome Statute, but only individuals are on trial in the criminal cases that come before the Court. 3 The Office of the Prosecutor has been empowered by the States Parties to bring criminal charges against individuals accused of violations of international criminal law.
There are many ways one could judge the ICC's performance. It might be evaluated based on its contribution to justice (Goodman and Jinks 2003), on its normative value (Bass 2003), on its capacity to offer societal "atonement" (Bikundo 2012), and/or on its legitimacy in the eyes of local victims (Clark 2011a). We will concentrate on examining the extent to which the ICC succeeds in achieving its desired outcomes (Introduction). The preamble of the Rome Statute makes it clear that the ICC's job is to improve the possibility of deterring the most egregious human rights violations and war crimes. The Court understands its own mission as being "to help end impunity for the perpetrators of the most serious crimes of concern to the international community." 4 Indeed, in its referral to the ICC, Uganda (the first state to refer a case to the Court) appealed for "the suppression of the most serious crimes of concern to the international community as a whole," although it is widely recognized in this case that the intent was to wield a legal threat against rebels alone. 5 At the same time, the purposes of the ICC were 3 States Parties may have an active role in admissibility proceedings. See for example Rome Statute, Articles 17-19. 4 ICC, at https://www.icc-cpi.int/en_menus/icc/about%20the%20court/Pages/about%20the%20court.aspx. 5 "Referral of the situation concerning the Lord's Resistance Army," submitted by The Republic of Uganda, 16 December 2003. At http://www.rohan.sdsu.edu/~abranch/Current%20Projects/Uganda%20ICC%20Referral%202003.pdf. The original referral reflects the government of Uganda's hope that the Court could be used to prosecute rebels alone. While this was in fact the decision of the Office of the Prosecutor (OTP) in this case, referrals inherently allow for investigation and indictments of any individuals. See the discussion in Nouwen (2103), pp. 114-115. to be achieved while protecting state sovereignty to prosecute crimes committed in their jurisdictions, through complementarity. 6 How should we then assess the performance of the Court? We present evidence of two kinds: first, we look for the imprint of the ICC on domestic law. In the case of the ICC, States Parties have strong incentives to reconcile domestic criminal statutes with international criminal law, since to do so allows them to take jurisdiction should they want to do so. 7 One of the major performance outcomes of the ICC is therefore the extent to which it has encouraged legal change within the domestic crime statutes of members. Second, we look for actual evidence that the ICC or the domestic laws it has encouraged have contributed to crime deterrence. Does the extension of the ICC jurisdiction through ratification actually deter the crimes it was designed to punish? Do changes in crime statutes that the ICC has stimulated done so?
Evidence exists that the ICC has performed well in this regard (Jo and Simmons 2016).
We discuss broad-based evidence of its deterrence effects, but we also focus in on a specific and very violent case: that of Uganda. We believe there is some evidence that the ICC has deterred some heinous crimes even in this difficult case. We discuss the evidence that the ICC's jurisdiction and action have deterred both state agents and rebel groups from committing atrocities against civilians in this case. In so doing, we recognize that this may not be what the government of Uganda originally intended when they ratified the ICC. Nonetheless, as the 6 Concerns about preserving state sovereign via carefully worded complementary jurisdiction was a strong emphasis of many states during negotiation of the ICC statute. See paragraphs 91-93 and 100 of the United Nations Report of the Ad Hoc Committee on the Establishment of an International Criminal Court General Assembly Official Records,Fiftieth Session Supplement No. 22 (A/50/22), Available at http://www.legal-tools.org/uploads/tx_ltpdb/doc21168.pdf. 7 A case is inadmissible when "The case is being investigated or prosecuted by a State which has jurisdiction over it" (Rome Statute, Article 17(1)(a)). If a states wants to have a credible objection to admissibility, then, there are clear incentives to define the crimes listed in Article 5(1)a-d in domestic criminal statutes.
introduction entreats us, we should look for evidence of court performance in individual cases as well as more broadly. The case of Uganda helps us to understand, in greater detail, just how international justice institutions, such as the ICC, become relevant on the ground.

I. Background on the ICC
The twentieth century has been a remarkable period of international judicialization. 8 International courts and court-like institutions have sprouted in surprising numbers to deal with specific functional problems, like conflict over trade agreements or disagreements over the application of the Law of the Sea, and regional concerns such as individual human rights. The ICC is different from nearly all of these institutions. Post-Cold War internal conflicts caused non-governmental human rights, humanitarian organizations, and some states 9 to call for an end to impunity for crimes against humanity and genocide (Lee 1999, Pace and Schense 2002, Glasius 2006. International Criminal Tribunals for the former Yugoslavia and then Rwanda primed the international community to think about the creation of the International Criminal Court (Tochilovsky 2003, Danner 2006. After several years of negotiation, a standing Court was established with the ability to prosecute high officials -even national leaders. Today, the ICC is the only international court devoted to the enforcement of international criminal law, holding 8 On the development of international law and judicial institutions over the past few decades see (Abbott 2000. On the development of "new style" ICs that give individuals a right to launch cases (in criminal cases, a prosecutor) see Alter (2011 (Danner 2003:513-15 13 While frivolous or politically-motivated prosecutions are a possibility (and one that has particularly concerned the United States), the Rome Statute has checks built into it to discourage a prosecutor from acting irresponsibly. These are described further in (Danner 2003 to presidential, parliamentary, or legislative officials in their domestic systems. 16 The result is a court much more independent of state control in the initiation of cases and far less protective of state sovereignty than was originally contemplated or has ever existed in modern history.
Enthusiasts of the ICC point out that its membership is very widespread. As of 2015, 123 states had ratified the Rome Statutes (Figure 1) [ Figure 1 about here] 16 Rome Statute, Art. 27. 17 We use the words "indict," "indictment" and "indictee" to refer to persons for whom the ICC has served warrants and related processes. The word "indict" does not appear in the Rome Statute.
This background information about the ICC powers and purposes are food for thought.
But its performance should be assessed systematically, and we suggest the best outcome performance measure is the extent to which the ICC has helped to deter the crimes within its jurisdiction. This can be done indirectly (through the development and encouragement of national capacities) and directly, by sending strong signals that impunity is a waning option.

II. The ICC and Deterrence: Theory and Mechanisms
In this section we justify our focus on the capacity of the ICC to deter crimes within its jurisdiction as one of the most important aspects of its performance, of which there are potentially many. We cannot possibly address all aspects of institutional performance in a single paper. Nor is our expertise in process performance. We therefore concentrate on outcome performance. Second, we refrain from attempting to read the minds of the creators of the ICC by devising creative interpretations of the Court's purposes. Instead, we take seriously the plain meaning of the words of the preamble of the Rome Statute: the ICC was meant, at least indirectly by addressing impunity, to contribute to the prevention of international crimes. For us, this means the ICC was designed to deter the kinds of atrocities that are within its jurisdiction.
Note this does not mean the ICC was created to put an end to war, although the preamble clearly expresses the idea that such crimes do "threaten the peace, security and well-being of the world…" Nor should the ICC be judged by the (inevitable) fact that some perpetrators may not actually face trials. The preamble is clear that the purpose of the ICC is to "put an end to impunity," which means that there should no longer be presumed exemption from punishment. 18 The extension of jurisdiction via ratification ends impunity understood as exemption. No one is exempt from consequences flowing from the obligation to refrain from committing crimes under the ICC's jurisdiction. International criminal law applies to all, whether or not a specific individual actually faces trial. The number of trials held is, for our purposes, only relevant insofar as it undermines the ability of the ICC to contribute to the prevention of international crimes.
The key performance indicator therefore should be: has the ICC contributed to crime deterrence?
We argue that it has. Prosecutorial deterrence refers to the omission of a criminal act out of fear of sanctions resulting from legal prosecution. People are increasingly likely to be deterred from violating the law when the chances and severity of a legal sanction, such as a fine, incarceration or capital punishment, increases. As such, law violation is a function of prosecution and sentencing. As the risk of more severe penalties is perceived to increase, the likelihood that an individual will commit a crime is reduced and the crime rate falls (holding any "utility" resulting from the violation constant).
For decades, the criminal deterrence literature has debated the question of exactly which elements of this rationalist model account for the deterrence of criminal behavior. The idea that severity of punishment largely drives deterrence (Grasmick and Bryjak 1980) fueled the move toward harsher sentencing in the United States in the 1980s. However, a growing consensus in the deterrence literature suggests that the swiftness and especially the likelihood of punishment may more effectively deter crime than severity of punishment (Kleiman 2009, Wright 2010. Empirical researchers employing surveys, experiments and scenarios also conclude that the likelihood of punishment is key for deterring crimes ranging from tax evasion to theft to sexual assault (Nagin andPaternoster 1993, Nagin 1998).
Raising the risk of punishment where the rule of law is otherwise weak is precisely the formal role envisioned for the ICC. The Court was designed to do this in two ways. The first is through its own authority to prosecute. The Court's jurisdiction applies to cases of genocide, crimes against humanity, and war crimes 19 that occurred after July 1, 2002 in the territory of a state that has ratified the treaty or that is committed by a national of such a state or in cases referred to it by the UN Security Council. 20 The Office of the Prosecutor ultimately decides which situations to pursue, but cases may be referred by member states (e.g., Uganda, the DRC, the Central African Republic, and Mali), the Security Council (Sudan and Libya), or initiated by the Prosecutor herself (Kenya and Côte d'Ivoire).
General deterrence is only possible if the Court's existence and actions raise the perceived likelihood that an individual will be tried and punished. Above we discussed the growing salience of international criminal law by various measures. To date, the ICC prosecutor has indicted more than 35 persons, and a further nine situations (involving Afghanistan, Honduras, Korea, Nigeria, Colombia, Georgia, Guinea, Palestine, and Ukraine) are under preliminary examination for jurisdiction and admissibility. Prosecutorial deterrence theory implies that investigations, indictments and especially successful prosecutions should trigger a 19 See Rome Statute, Article 5. We refer to these below as "ICC crimes" or "international crimes." 20 Rome Statute, Art.12(2); Chapter VIII covers UNSC authority to refer. reassessment of the likelihood of punishment and a boost to general deterrence (Geerken and Gove 1975) -a result consistent with Kim and Sikkink's (2010) study of national human rights trials in transition countries.
The most common rejoinder of ICC skeptics is that nine investigations and 35 indictments is not much, and not enough to affect the behavior of governments and rebels locked in violent conflict with each other with civilians as pawns often in between. Our first response is that 35 indictments is considerable, compared to impunity. But moreover, there is no reason we should suppose governments and rebels sift through evidence in a completely objective way.
These actors are as susceptible as any other with a human brain in their heads to biases produced by availability heuristics. Availability heuristics, for example, make it far more likely that people will remember ICC investigations and warrants rather than their lack, as well as convictions rather than acquittals. The former are salient while the latter often go unnoticed. Just as an example, a look at google trends for 2012 shows a significant search trend for Thomas Lubanga Dyilo (who was convicted for war crimes in March 2012) yet nothing but a flat line for Mathieu Ngudjolo Chui (who was acquitted for similar crimes in December that same year). The name of the convicted man also has about 30 per cent more google hits, and 230 per cent more press coverage, as measured by articles in the Lexis-Nexis database, than the name of the acquitted man. Conviction is news; acquittal, not so much. 21 Note we are not claiming that rebels and government officials do these searches; we are simply demonstrating that small numbers of convictions do not undercut our deterrence argument for well-known psychological 21 The trial of Slobodan Milosevic provided an exceptionally poignant image of a national leader subjected to the humiliation of an international trial.
reasons. Arguably, the ICC is an institution that is likely to make the risk of punishment both salient and vivid.
The common rejoinder also neglects a crucial indirect deterrence mechanism. The Rome Statute's "complementarity regime" creates a channel for the ICC to support prosecutorial deterrence at the national level as well. The ICC is designed to complement, and not to preempt or substitute for national prosecution. 22  . We are not naïve enough to believe any of these cases represent international standards of justice, nor do they overturn the prevalent culture 28 The trials variable is from Kim and Sikkink (2011). The correlation coefficient between reform and human rights trials is .176 (p-value: 0.000). Spearman correlation test for ordered variables returns a similar result. Spearman's rho is 0.166 with p-value of 0.000. 29 Sikkink (2011-2012) also find quantitative as well as qualitative evidence that "countries that ratify treaties protecting core rights with individual accountability provisions are more likely to use human rights prosecutions than countries that have not ratified these treaties (751)." 30 Opinions vary as to whether the trial was impartial, credible and fair Nouwen (2012a) notes that "The prosecution of Kwoyelo was prompted by opportunism rather than law or policy. Kwoyelo is considered of little use by the ruling party. Rather, Kwoyelo, as a Ugandan 'Tadic', could satisfy the ICD's institutional craving for a first case, and during the ICC Review Conference in Kampala the preparations for his case served to demonstrate the host country's commitment to international justice at home" (p.221-2). See also Nouwen 2012b: "Critics charge that Kwoyelo was politically convenient; his submission for amnesty was ignored; it was a political show before the Ugandan government hosted the ICC Review Conference in 2010; and that it was the only trial thus far taken up by the ICD." 31 See also the Transitional Justice Research Collaborative, events history data on human rights trials https://transitionaljusticedata.com/. of impunity in these and similar cases, but they do suggest that some institutional change has occurred in some of the worst cases in which the ICC has had an influence.
In sum, we argue that ICC performance should be assessed in terms of its ability to deter the kinds of crimes under its jurisdiction. The ICC and the norms it embodies are highly salient institutions that have caught the attention of would-be perpetrators, and influence them to reassess their prospects for apprehension and punishment. Prosecutorial deterrence is therefore enhanced by conditions that make prosecution more likely in a given jurisdiction, such as ratification of the Rome Statute, passage of ICC implementing legislation, national trials or court reforms that make trials more probable and credible. 32 In the next section, we discuss the evidence for these propositions in one of the most violent cases: that of Uganda.

III. ICC's Deterrence Potential in Uganda
Uganda is one among eight situations currently on the ICC docket.  (Branch 2011) and are cynical about the Ugandan government's 32 On the phenomenon of "enforcement spillovers" by which monitoring and enforcement increases compliance even in areas without monitoring or enforcement see Rincke and Traxler (2010).
self-referral to the Court, suspecting the Court's bias (Clark 2011b  The demonstrated willingness of the ICC to prosecute may also have encouraged some changes in domestic law, institutions and practice. After ICC ratification, Uganda began to reform its own capacity to detect and deter war crimes (Witte 2011). As noted in polls discussed above, in the mid-2000s, Ugandans had much more confidence in the ICC than in their own legal system. But since its encounter with the ICC, the state has invested in its domestic court system's capacity to try war crimes and crimes against humanity (Nouwen 2012 Investigation and the ICC's issuance of Arrest Warrants. Figure 2 shows that Uganda's signature on the Rome Statute and issue of arrest warrants for rebel leaders did little to perturb the series.

ICC and Ugandan Military Attacks
In fact, there is a considerable spike in rebel attacks on civilians associated with ratification, though this is likely attributable to the launch of Operation Iron Fist than with any action by the ICC. But more crucially, there is a precipitous fall in fatal attacks on civilians by rebels occurring just after the ICC began investigation of the situation in Uganda.

Time Series Intervention Analysis
Is the ICC in some way responsible for this welcome decline? In order to answer this question, we conduct a time-series intervention analysis. We use the logged fatalities in Figure 2 as the dependent variable due to a couple of outlier events. 39 The intervention method allows us to determine whether there is a statistically significant difference in the level of a group's violence before and after an ICC intervention, while accounting for alternative explanations as well as the series' random component. If we observe no difference, then we have no reason to 39 In particular, there are two extreme outliers for December 2008 and December 2009, which are nearly 3 and 4 times larger than the next highest data point, respectively. These outliers correspond to the Christmas and Makombo Massacres in northeast DRC. Without logging, outliers can cause our analysis to falsely present mean shifts that are not there. Logging the measure also helps with concerns that the series does not have variance stationarity.
believe that the ICC affected the outcome. But if we observe a difference over time, we will have some evidence that the ICC affected the pattern of violence.
Intervention analysis involves two modeling decisions: whether the effects are permanent (mean-shifting) or temporary (non-mean-shifting) and whether the effects are abrupt or gradual (that is, the rate at which the effects appear and subside). The effects reported in these models are assumed to permanently and abruptly shift the mean. Key events associated with the ICC constitute a "change of state" within Uganda and we expect them to have a "permanent" impact on the behavior of LRA. Additionally, we expect any change to be rather "abrupt" because these ICC events are expected to have a major impact on the lives of key leaders in the LRA, who have strong incentives to keep themselves informed and to change their behavior almost immediately. 40 In order to model the effects of events as permanent and abrupt shifts, each independent variable (binary indicators for Signature, Ratification, Investigation, and Warrants) is coded as 0 for every month before the event and as 1 for every month after the event. 41 Since interventional analysis can lead to spurious results when key events of interest are correlated with other factors and events, we use two strategies to ensure that our results are robust: controlling for rival events. For rival events, we include events other than ICC actions that likely caused the level of fighting to escalate or diminish. We control for two military operations: one by the Ugandan government (Operation Iron Fist) and one by the government of 40 We also checked the results with different combinations of modeling assumptions: (permanent, gradual), (temporary, abrupt), and (temporary, gradual). Permanent and abrupt models provide the best fit. 41 . In the time-series analysis of multiple interventions, the influence of each intervention only holds until the next event (see Montgomery, et al 2015, pg. 471).

the DRC (Operations Rudia I). Moreover, we include a variable for the effect of the Juba Peace
Talks and the introduction of the United States as a conflict actor with the passage of the LRA Disarmament Act. We also use a more general variable, Battles, which is the monthly count of battles between the LRA and governmental or international forces. The LRA's propensity to exhibit violence towards civilians might also have been the result of their wartime fortunes.
Defeats might have left the group more desperate for civilian support and supplies causing them to use violence and coercion as a means to secure these necessities. We use a variable to account for this military balance (Government Territory Gain), which are monthly counts of battles in which the government claimed territory. The purpose of these controls is to minimize the possibility that we are misattributing a reduction in violence toward civilians to the ICC rather than to other battlefield conditions. [  Table 3 shows the results of intervention analysis with these four different series. 44 The key takeaway from this table is that civilian killing was not replaced by other forms of violence. The ICC investigation led to a statistically significant decrease in both LRA attacks with civilian deaths (Killings) as well as those incidents that were atrocious but non-lethal (Kidnappings, Pillaging and Scorched Earth). 42 There is a similar pattern between logged fatalities and battles. The correlation between the series is 0.68 before the investigation and falls to 0.28 after. 43 The authors used the "Notes" sections within ACLED's country-level datasets to ascertain these descriptions. effective means of civilian protection; these "safe havens" were still located in Northern Uganda and were frequently attacked by the LRA (Mills 2015). In fact, when we isolated attacks to only those that occurred at IDP camps, we found a very similar pattern to that of the violence at large. 46 Third, and finally, the conflict was mostly confined to three northern regions-Acholi, Lango and Teso-but the majority of displacement was in Acholi. Our additional analysis shows that the ICC investigation had a statistically significant downwards effect on the number of attacks and civilian fatalities for both the Acholi region and regions lying outside of Acholi. 47 We take it as evidence that civilian displacement does not affect our conclusion about the ICC deterrence effect.

IV. Conclusions
The world's first international criminal court has been a game-changer in international We test these claims in the context of an especially violent case: the Ugandan civil war.
While some might argue that the Ugandan government ratified the Rome Statutes primarily to unleash the ICC on its political and military opponent, we found that, with the involvement of the ICC, the government strengthened criminal statutes, improve monitoring of its own military, and even prosecuted some of its own soldiers for atrocities. Of course, simply announcing an investigation is not likely on its own to deter atrocities. Visible and ongoing involvement of the ICC and clear indications of international support are likely to be necessary to send a clear signal about the end of impunity. Nor do we claim that the ICC has revolutionized the rule of law in Uganda. To be sure, there is much room for improvement in local justice. But the evidence suggests ICC-inspired movement in a modestly positive direction.
We also took the case to systematic statistical analysis to see whether ICC interventions matter on the ground; that is, whether the ICC has contributed to a reduction of violence against civilians. We are fully aware that Uganda constitutes just one case, and that one must be careful about generalizing. 48 Nonetheless, the results are striking. Using time series intervention analysis, we found highly suggestive evidence that ICC actions, and in particular investigations, have discouraged rebels from intentionally killing civilians. Some might raise the concern that this case illustrates the risks of government impunity, since the Court only charged rebel leaders.
Regarding this possibility, however, we remind readers that nearly half of the individuals wanted for ICC trial have been government officials.
48 But note that these results for Uganda are consistent with a broader set of all civil war cases analyzed in Jo and Simmons (2016). We do not claim the ICC deters in every case, but rather that it reduces intentional killing on average, and especially where it has ongoing investigation underway.
Certainly, the ICC faces many challenges ahead. Efforts by the African Union to undermine the Court's legitimacy could fuel backlash. Kenyatta's apparent "win" represented by the ICC's decision to drop charges against him could undermine some of the positive developments we have discussed in this article. U.S. cooperation remains episodic, although the January 2015 surrender and transfer of Dominic Ongwen via the Central African Republic to The Hague for trial with American assistance is a positive sign. The surrender of this child-soldierturned-LRA-commander constitutes "…the first commander of an internationally listed terrorist organization to give acte de presence at the [ICC]." 49 We also note that trials generally have not delayed peacemaking in ways that early detractors predicted (Dancy and Wiebelhaus-Brahm 2015). Much remains to be done to assess the consequences of the turn to develop and enforce international criminal law, but this research suggests some important positive effects. 49 See http://africanarguments.org/2015/01/20/dominic-ongwen-born-at-the-time-of-the-white-ant-triedby-the-icc-by-thijs-b-bouwknegt/.