This summer marked the 50th anniversary of Northern Ireland’s Troubles, a decades-long ethnic civil war that killed more than 3,000 people. The war lasted until 1998, when the Good Friday Agreement reaffirmed British control of Northern Ireland but offered Catholics assurances against government discrimination and the gerrymandering that had previously limited their voice in Northern Ireland’s government.
Today, Northern Ireland’s Catholics and Protestants have equal reason to regret the conflict. Thirty years of war, thousands dead and a peace settlement that cannot heal the psychological scars—why did all of this happen? Some new political science research sheds some light on this question. It may also carry lessons for Americans who worry about social divisions and violence in our own time.
Catholics and Protestants in Belfast came to adjust their daily commutes and shopping routines to avoid street interactions with the religious “other.”
Our research shows that the most diverse neighborhoods of Northern Ireland’s capital, Belfast, experienced the most conflict-related deaths, a total of 1,617 within the city limits. “Interfaces,” where Catholic neighborhoods directly abutted Protestant neighborhoods, were exceptionally deadly sites.

At first, this finding seems to support the argument for separating different ethnic and religious groups—partitioning neighborhoods, restricting immigration and hardening borders to prevent ethnic and religious “others” from entering one’s own community. (The “peace walls” built to separate Catholic and Protestant enclaves in Belfast are the physical embodiment of this strategy.) But a closer look at Belfast and a comparison with other ethnically divided societies give us reason to question the wisdom of partition.