When coalition troops arrived to enforce the Dayton peace agreement late in 1995, they interjected themselves between the tanks, earthworks and howitzers of armies that had been fighting days before.

They set up what is called the "interboundary entity line," said Lt. Col. James B. Cronin, spokesman for the Coalition Press Information Center here. Eagle Base, about 11 miles southeast of Tuzla in eastern Bosnia, is headquarters for the 8,000 or 8,500 American soldiers in Bosnia."That's basically where the war stopped, for the most part. And what we did, we separated them, four kilometers from that line," said Cronin, a Chicago resident.

The line was needed to keep enemies off each other's throats. During the war, armies representing Bosnia's three ethnic groups tried to consolidate territory. In the process, Europe suffered its worst genocide since the Nazi era.

Under the Dayton Peace Accords, Bosnians of all ethnic backgrounds have the right to return freely to their homes. The agreement is what allowed the coalition forces to intervene. It was signed by all parties to the conflict. It is enforced by the 30,000 coalition troops.

Yet 2 1/2 years after the intervention, the interboundary entity line remains in place. Most Bosnians would not consider crossing it, for fear of what the people on the other side would do to them.

"Why is that so complicated?" Cronin asked, then quickly answered himself.

"All of Bosnia is less than 4 million people. They lost 200,000 in the war. Think about that: That's one out of every 20 people died during this war. . . . A million people were either resettled or became refugees - half the population."

In the peacekeepers' lingo, a refugee is a person who has left Bosnia. A displaced person still lives in Bosnia but has been forced away from home.

Around 350,000 Bosnian refugees live in Germany, with that country paying for housing and food. Another 100,000 are in Sweden, and others are throughout Europe, he said. "Some of them are in America.

About 1 million displaced people were resettled in the Serb-controlled Republika Srpska or in the federation of Croats and Muslims, he said.

Many now live in homes that originally belonged to Bosnians of other ethnic backgrounds. To move a Muslim family back to the Republika Srpska might require displacing a Serb family that now lives in that house.

For example, he said, consider Srebrenica.

"Srebrenica before the war was about 100 percent Bosnian Muslim. Srebrenica today is 100 percent Bosnian Serbs."

Further complicating the political landscape, the Dayton agreement says Bosnians must be allowed to vote in local elections if they live in an area now or used to live there.

Last September, Muslims who were chased away from Srebrenica during the atrocities could vote in the town's municipal elections, even though they no longer lived there.

"Well, guess what? Who won the election in Srebrenica?" Cronin said.

"The SDP Muslim Party won the majority of seats in Srebrenica. The party that won the election had not one person living in that place. So, we still have not been able to have an initial meeting where we got the elected people in charge of the city."

Srebrenica's present residents aren't the soldiers who chased away or slaughtered the original people. "They're not responsible for the atrocities that took place," he said. Many are displaced people themselves from Sarajevo, Serbs who fled the Federation of Croats and Muslims.

When Cronin visited Srebrenica this spring, he found people who had no running water, no heat in their schools. "The buildings have all been destroyed. The people are living in total abject poverty," he said.

The reason they were so badly off is that the international community decided that the Federation was doing a good job of living up to the Dayton Accords while the Bosnian Serbs weren't, so it directed most of its aid toward the Muslims and Croats.

"It's kind of hard to convince these people that Dayton's the thing to do when you're living in those kinds of conditions." Lately, however, he said, an improved attitude by the Bosnian Serb leaders promises to bring more aid.

In many parts of Bosnia, mobs attack returning refugees, forcing them away from their former homes. Many are unwilling to try to go home to their old villages.

"Quite frankly, a lot of them just don't feel safe," Cronin said. "There's still so much animosity."