Biden considers his most important foreign policy accomplishment to be his leadership on the Balkans in the mid-1990s. He pushed a reluctant Clinton administration first to arm Serbian Muslims and then to use U.S. air power to suppress conflict in Serbia and Kosovo.
In his book, "Promises to Keep," Biden calls this one of his two "proudest moments in public life," along with the Violence Against Women Act that he championed.
In 1998, he worked with McCain on a resolution to push the Clinton administration to use all available force to confront Serbian leader Slobodan Milosevic, a move designed to force the president to use ground troops if necessary against Serb forces in the former Yugoslavia, which was beset by fighting and ethnic cleansing.
When the current Bush administration began pushing for war with Iraq, Biden was less enthusiastic. He had voted against authorization for the Persian Gulf War in 1991. Now he joined Lugar in drafting legislation that would have authorized the president to take action to eliminate weapons of mass destruction in Iraq but not to remove Saddam Hussein.
And the two senators wanted to require United Nations authorization before any military action could be taken.
Biden was undercut, however, by House Democratic Leader Richard A. Gephardt, who got behind a more sweeping war authorization. Biden nonetheless voted for the war authorization.
Biden became a war critic not long after the invasion. But he was never among those Democratic senators -- such as Russell D. Feingold of Wisconsin and John F. Kerry of Massachusetts -- who pushed most forcefully to mandate a U.S. withdrawal.
Instead, Biden teamed with journalist and former U.S. official Leslie H. Gelb on a plan encouraging broad autonomy for the Shiites, Sunnis and Kurds. Gelb had initially developed the so-called federalism idea and, he said, convinced Biden to get on board when the two were sitting next to one another while stuck on the tarmac for 3 1/2 hours on a New York-to-Washington flight.
"There isn't much of an ideology with Joe," said Gelb, who has become a big fan of Biden's. "He's very pragmatic. He studies a problem and tries to figure out what the interests are and where the solutions will be."
The federalism plan was one of the few comprehensive alternatives to what the Bush administration was doing in Iraq and also one of the few legislative efforts to win any Republican support. Conservative Sens. Sam Brownback of Kansas and Kay Bailey Hutchison of Texas were early supporters.