With their initials this week, Balkan leaders may end a long conflict, but their peace agreement issues a fresh challenge to Serbs, Croats and Muslims to control historic animosities, and it is likely to provoke political warfare on a new battlefield, the U.S. Congress.

The Tuesday treaty signing produced more negative reaction than relief. The lukewarm assessments from politicians and commentators are understandable.

Forty-three months of combat between ethnic forces in the former Yugoslavia produced some of the most brutal fighting and horrifying atrocities since the end of World War II. The nearly four-year-long period of mayhem cost an estimated 250,000 human lives, left physical and psychological wounds in many times that number of people and deepened tribal and religious hatreds that have simmered for generations.

The agreement came as a surprise. After three weeks of trying, the presidents of Serbia, Bosnia and Croatia had tenatatively agreed on constitutional issues, but seemed bogged down on the division of territory. Given the checkered history of United Nations and NATO peacekeeping efforts, especially in Somalia and Bosnia, there is little enthusiasm to send into harm’s way 60,000 NATO troops, one third of them American, to police a 2 1/2-mile-wide demilitarized zone.

The Dayton treaty is a fat target for skeptics, but it has the potential to heal human divisions in the Balkans even as it creates new political boundaries.

It deserves a fair and thorough hearing in Congress, which should handle this issue as it did President George Bush’s proposal to send troops to Saudia Arabia and Kuwait. Much like it did for the Middle East, Congress must debate U.S. interests in bringing order to a destabilized region and weigh the value of greater global stability against the risk to American lives.

Senators and representatives first should determine if within the treaty framework there is sufficient peace to protect, examine the rules of engagement, and be certain NATO and American forces have the authority, troop strength and firepower to defend themselves. Then, Congress should vote directly and clearly on this military enterprise, as it did for the Persian Gulf.

Troops should be sent to Bosnia on one condition. They must leave from a firm political base here at home that is built on public, presidential and congressional support. Anything less is unacceptable.