In 1991–2, several territories of the Socialist Federal Republic (SFR) of Yugoslavia declared independence. Although Macedonia and Slovenia gained autonomy quickly and relatively peacefully, ethnically driven wars resulted in Croatia (1991–5) and Bosnia–Herzegovina (1992–5). After UN forces were installed in Croatia in February 1992, the focus shifted to Bosnia–Herzegovina with the outbreak of civil war among ethnic Croats, Serbs, and Bosniaks. The decision by the United States and its NATO allies to intervene in the civil war in Bosnia to stop ethnic “cleansing” and genocide followed a protracted debate about the wisdom of this policy. During the various Balkan wars – which included Kosovo in 1996–9 – the United States, UN, NATO, and members of the international community watched as “ethnically based criminal violence” by “the majority population – Muslim, Serb, or Croat – cleansed its community of now unwanted minorities.”

This crisis during the 1990s became the symbol of the protracted ethnic, national, and religious wars that are difficult for outside states to address, to ignore when those conflicts involve crimes against humanity, or to resolve with outcomes that resemble victory. The U.S.–European decision to intervene in Bosnia, which evolved over several years, was organized in several discrete phases: protecting UN humanitarian-relief efforts as of July 1992; NATO no-fly zones as of April 1993; campaigning in May 1993 for the selective lifting of a UN-imposed arms embargo and conducting air strikes; deciding later that month to pursue a policy of containment; pushing for a negotiated settlement through a diplomatic “endgame strategy” developed in the summer of 1995; and participating in the two-week NATO air campaign that began in late August.