Ten years ago, at the Wright-Patterson Air Force Base outside Dayton, Ohio, the leaders who had waged a brutal four-year war in Bosnia -- at the center of a volatile region that had launched two world wars -- finally agreed to peace. They took this momentous step only after intense international military and diplomatic pressure led by the United States. At the time, almost everyone predicted that the Dayton Peace Agreement would fail.

To enforce the agreement, I sent 20,000 U.S. soldiers to Bosnia as part of a 60,000-troop NATO peacekeeping force, because it was the only way to ensure that the Dayton Agreement was more than words on a page. For three winters, the people of Sarajevo had inspired us all with their courage in the face of snipers, hunger and bitter cold. After the genocide of 1995, when more than 7,000 men were murdered in Srebrenica, it was clear that only NATO under America's leadership could ensure peace.

Still, a large majority of the American public opposed my decision. Some expected heavy casualties; some feared another round of war, with Bosnia split in two and the need for our troops never-ending. On the day before the Dayton Agreement was to take effect, the House of Representatives voted three-to-one against an American troop deployment to Bosnia. Despite this opposition, I felt the United States had to act in order to stop the atrocities and try to bring peace and stability to the region.

Ten years later, the people of Bosnia have validated those who stood with them. Dayton ended the war. It will not resume. The region is now stable and peaceful, and the brutal killings are only a memory, albeit a painful one for the many families who lost loved ones. In 10 years there have been no American or NATO casualties from hostile action and troop levels are now down to 7,000 overall, of which fewer than 200 are American.

Bosnia is one country. It does have two distinct entities, one Serb and one a Croat-Muslim Federation, but movement is unimpeded across the boundary line and there are no troops or roadblocks on that line. The country has a single currency and a single economy. Bosnia had more than 400,000 people under arms in 1995; today it has fewer than 10,000. Just under half the displaced people have returned, many of them to areas where they constitute a minority. Almost no one dared to predict these successes a decade ago.

To be sure, Dayton was not a perfect peace. It is hard to imagine such a thing. But it achieved vital national security interests. It ended the worst war in Europe in half a century, which threatened the peaceful integration of Europe after the Cold War. It, and subsequent events in Kosovo, laid the basis for a multiethnic state, which has lived in peace for a decade with its neighbors. It triggered the events that led to the dictator Slobodan Milosevic's removal and trial at The Hague for war crimes....