Warren Zimmermann (November 16, 1934 – February 3, 2004) was an American career diplomat best known as the last US ambassador to SFR Yugoslavia before its disintegration in a series of civil wars. Zimmermann was a member of the Yale Class of 1956, and a member of Scroll and Key Society. He died of pancreatic cancer at his home in Great Falls, Virginia on February 3, 2004. Career Warren Zimmermann served in Moscow (1973–75 and 1981–84), Paris, Caracas and Vienna, where he headed the US delegation at the Conference on Security and Cooperation in Europe (1986–89). But it was Yugoslavia that marked him more than any other phase in his professional life, and brought him to prominence. Bosnian War Zimmermann played an active diplomatic and geopolitical role during the initial stages of the Bosnian War. According to Robert W. Tucker, Professor Emeritus of American Foreign Policy at Johns Hopkins University and David C. Hendrickson, a Professor at Colorado College, Zimmermann may have scuttled the Lisbon Agreement also known as Carrington-Cutileiro peace plan. That was an agreement that would have made peace between three main ethnicities, Bosniaks, Serbs, and Croats, living within the bounds of Bosnia and Herzegovina by the creation of a cantons system, such as exist in Switzerland. At a time when Bosnia-Herzegovina was sliding into war along ethnic lines, this plan proposed ethnic power-sharing on all administrative levels and the devolution of central government to local ethnic communities. On 28 March 1992, ten days after the agreement had been signed by each of the three sides, Zimmermann came to Sarajevo to meet with Alija Izetbegović, president of the Presidency of Bosnia and Herzegovina, giving Izetbegović assurances of U.S. support for a full independent nation without internal division. Within days of meeting Zimmermann, Izetbegović withdrew his signature and renounced the peace plan he agreed to in Lisbon, suddenly declaring his opposition to any type of ethnic division of Bosnia and Herzegovina. Within weeks a full blown war developed. Three and a half years later, the Dayton Accord that all three sides accepted in November 1995 thus ending the war, featured a very similar canton system, dividing Bosnia-Herzegovina internally along ethnic lines. Writing in 1997, Alfred Sherman, British political analyst and an adviser to Margaret Thatcher, described Zimmermann's involvement in Bosnia, along with American overall foreign policy in the Balkans, as: "lying and cheating, fomenting war in which civilians are