Hooper, co-director of the Balkan Institute, is a former senior U.S. diplomat who served most recently as Deputy Chief of Mission at the U.S. Embassy in Warsaw, Poland.

Serbia's war against Bosnia and Croatia between 1991 and 1995 was characterized by appalling acts of systematic violence against civilians. The use of ethnic cleansing and other genocidal tactics by Serbian strongman Slobodan Milosevic as a policy tool for partitioning Bosnia and Croatia and establishing a new population balance favorable to the Serbs in ethnically-cleansed territories shocked the international community.

Because of the genocidal nature of the conflict, it was impossible for negotiators to ignore the issue of war crimes and the prosecution of war criminals. Almost two years earlier, on May 25, 1993 the United Nations, in a Security Council vote, had created the International Criminal Tribunal for the Former Yugoslavia, located in The Hague, to prosecute those responsible for perpetrating serious violations of international humanitarian law. U.N. Security Council Resolution 827 determined "that all States shall cooperate fully with the International Tribunaläandätake any measures necessary under their domestic law to implement the provisions of theäresolutionäincluding the obligation of States to comply with requests for assistance or orders issued" by the Tribunal.

Antonio Cassese, the Tribunal's first President, described its mission as threefold: "to do justice, to deter further crimes and to contribute to the restoration and maintenance of peace." By prosecuting war criminals, the Tribunal would remove the stigma of collective guilt from the peoples involved in the conflict and shift responsibility for war crimes to their leaders, who ordered or carried out crimes against humanity. Removing war criminals from the scene would prevent them from continuing to block peace and enable a process of healing and reconciliation to move forward. By establishing the principle of accountability for war crimes, the Tribunal would contribute to the deterrence of further genocidal conflict.

U.S. negotiators at Dayton, recognizing the linkage between security and justice, believed that holding war criminals accountable for their actions would help secure a sustainable peace with justice in Bosnia and Croatia. The final agreement, initialed at Dayton on November 21 and formally signed in Paris on December 14, contained not only language to implement the cease-fire, but also included several references to war criminals. The agreement stipulated that no individual indicted by or serving a sentence imposed by the U.N. War Crimes Tribunal would be allowed to hold any appointive, elective or other public office. The "Parties" (Bosnia, Croatia and Serbia) to the conflict were required to cooperate with the Tribunal and comply with any of its requests for the arrest, detention, surrender of, or access to military prisoners - or civilians held in relation to the conflict - indicted by the Tribunal.

However, the fulfillment of these aims requires the support of the NATO powers, led by the United States. While governments in the region have an obligation to surrender indictees, government officials have proven unwilling to turn their supporters over to the Tribunal for trial. NATO must, therefore, assume primary responsibility for apprehending indicted war criminals and delivering them to The Hague.

The Military Annex to the Dayton agreement "authorize[d] the IFOR [Implementation Force]to take such actions as required, including the use of necessary force, to ensure compliance with this Annex, and to ensure its own protection." But the agreement did not oblige IFOR to apprehend or transfer to the custody of the Tribunal suspected war criminals, or otherwise facilitate the work of the Tribunal.

U.S. military representatives at Dayton explained to the Bosnians that they did not want an explicit requirement in the agreement to apprehend indicted war criminals. The Bosnian delegation, however, obtained an implicit promise from the NATO representatives regarding apprehension of war criminals. According to the Bosnian delegation's American legal adviser, former State Department official Paul Williams, the NATO-led international peacekeeping force in Bosnia "would neither interact with indicted war criminals nor tolerate their presence in the area of operation. The parties took this to mean that NATO forces would actively participate in the apprehension of indicted war criminals." This interpretation turned out to be wrong.

Politics and diplomacy cast a long shadow over decisions by the Dayton peace negotiators on how to treat the principal architects of genocide: then-Serbian President Slobodan Milosevic (who has since become president of the Serbian-Montenegrin Federation), Bosnian Serb political leader Radovan Karadzic and Bosnian Serb military commander Ratko Mladic. Negotiators were aware of the precedent set by the Nuremberg trials following World War II, where allied leaders agreed that surviving senior Nazi officials who had made the fundamental German war crimes-related policy decisions should be tried along with lesser officials who implemented these policies.

At Dayton, this precedent was stood on its head. Senior American officials assumed that the indictment of Milosevic - who had instigated the war and formulated the policy of ethnic cleansing in Bosnia and Croatia - would undermine his commitment to implement the peace agreement, thereby increasing the risk of casualties for NATO peacekeepers.

The Dayton negotiators were also reluctant to order the arrest of Karadzic and Mladic, who - unlike Milosevic - had been indicted not only once but twice. As in the case of Milosevic, U.S. and allied leaders feared that the apprehension of the two most senior Bosnian Serb indictees would spark Bosnian Serb retaliation to the peace accords and risk the lives of NATO troops. (To date, the arrest order for Karadzic and Mladic still has not been made.)

Thus the Dayton negotiators allowed Karadzic to remain at large and free to organize opposition to the peace accords. They thought they had obtained Milosevic's agreement, however, to force Karadzic to relinquish his post as Bosnian Serb president and "be removed from public life." When it later became clear that Milosevic was failing to abide by this understanding, President Clinton sent envoys to meet with Milosevic several more times to persuade him to remove Karadzic from politics. American troops were not ordered to apprehend Mladic, who resided in the American zone in Bosnia for at least two years following the Dayton agreement and traveled freely between Bosnia and Serbia-Montenegro.

Expectations that the Dayton agreement would produce a breakthrough on apprehension of indicted war criminals were dashed almost immediately by the United States, Dayton's chief sponsor. The Pentagon feared that involvement of IFOR (the Implementation Force of NATO and non-NATO peacekeepers, which was renamed SFOR, the Stabilization Force, in December 1996, after the U.S.-imposed one-year mandate for IFOR expired) troops in operations to arrest indicted war criminals would expose U.S. soldiers to retaliation. Pentagon officials argued that American casualties would undermine public and congressional support for Dayton. President Clinton, who as commander in chief has final authority in all such matters, acquiesced to this approach. The NATO allies shared similar domestic political risk assessments of their own.

The Pentagon drafted rules of engagement for IFOR troops, therefore, that reflected a minimalist interpretation of Dayton commitments to apprehend indicted war criminals. These guidelines stipulated that IFOR would not hunt down indicted war criminals but would arrest them only if IFOR came into contact with them in the course of their routine duties and only if the tactical situation allowed. In theory, this meant that indicted war criminals identified, for example, while seeking to cross IFOR checkpoints were subject to arrest. It also meant that war criminals that IFOR troops came upon while patrolling towns and roads would be apprehended.

But this minimalist approach was further diluted in practice. IFOR ensured that these rules of engagement were publicized throughout Bosnia, intentionally conveying the set of understandings to which indictees could adapt in order to evade capture. IFOR/SFOR troops, moreover, systematically ignored even these rules in their determination to go to any lengths to avoid confrontations with indicted war criminals. Credible reports surfaced of IFOR/SFOR allowing indicted war criminals to pass through checkpoints and allowing indictees to move about openly in regularly patrolled towns. At times, IFOR troops even left areas that they had been patrolling to avoid encounters with indictees. NATO was also initially reluctant to distribute lists and descriptions of indicted war criminals to IFOR troops that would enable them to identify indictees.

From the signing of the Dayton agreement in December 1995 until the summer of 1997, NATO avoided active measures to apprehend indicted war criminals. This reportedly infuriated the tribunal's second Prosecutor, Louise Arbour, who decided to prepare secret indictments and requested that NATO act on them. NATO commanders reportedly were concerned that, under existing rules of engagement secretly indicted war criminals might unwittingly come into contact with ‚ read: would not know to avoid-- SFOR troops, who would be required to arrest them. Concluding that it would be too risky to leave such confrontations to chance, NATO commanders reversed their approach: they decided it would be more prudent to take a pro-active role in apprehending secret indictees.

The first fruit of this policy was the operation by British SAS commandos in Prijedor on July 10, 1997 against two secret indictees, one of whom was apprehended and the other killed while resisting arrest. Despite worst-case NATO warnings, retaliation for apprehensions of Bosnian Serb and Croat war criminals has been sporadic and inconsequential, with no NATO troops killed in the process.

The issuance of secret indictments was not the only factor prompting a more active NATO apprehension policy. The emergence of more pragmatic Bosnian Serb leaders less inflexibly opposed to Dayton, including President Biljana Plavsic and especially Prime Minister Milorad Dodik, meant that NATO would have possible allies in the struggle against hardline Bosnian Serbs. NATO began to view indicted war criminals more as a threat to Bosnian Serb reform efforts than to SFOR troops.

The election of Dodik as prime minister of the Bosnian Serb entity in January finally brought to the fore a Bosnian Serb leader prepared to shoulder some of the risks for persuading indicted war criminals to turn themselves in or, at a minimum, willing to order his police apparatus not to organize resistance to NATO-led apprehension operations. For nearly two years NATO had hid behind the language of Dayton calling on "the parties" to take responsibility for apprehension rather than risking the lives of NATO troops to apprehend Serb and Croat indictees. Dodik's willingness to take risks helped persuade Washington to follow suit.

Persistent efforts by the NGO community also helped persuade NATO to be more active in bringing war criminals to justice. The NGOs aroused public concern and mobilized congressional opinion in the U.S. to remind the administration of the threats to U.S. policy posed by war criminals remaining at large.