Even Americans unschooled in the history of the Middle East know that Iraq comprises Sunni, Shia and Kurdish Muslims, thanks to the Bush administration's much-publicized effort to promote reconciliation among those groups. Often overlooked is the fact that Iraq has an ancient Christian population that has suffered grievously from the instability that followed the U.S. invasion.

More than 1,300 Christians recently fled the city of Mosul after 14 were killed -- perhaps by Al Qaeda in Iraq -- following a protest about an election law that didn't provide Christians with fair representation on provincial councils. But that is only the latest exodus of Christians from Mosul, which served as a refuge for those driven out of Baghdad, and from Iraq as a whole. A Chaldean Catholic archbishop has warned that Christians in his country face "liquidation."...

...The religious cleansing of Christians in Iraq is part of a larger pattern in which a faith with origins in the Middle East is being driven out of its native region. From Iraq to Lebanon, which once claimed a Christian majority, to Bethlehem, the West Bank town revered as the birthplace of Jesus, intra-Muslim violence and the Arab-Israeli struggle have combined to persuade (and in some cases force) Christians to relocate to Europe or North America.

This is a tragedy not only for Christianity but also for the long-term goal of ensuring Middle Eastern societies that are pluralist as well as democratic. Christians in the Middle East haven't always promoted such virtues. Maronite Catholics in Lebanon sought to deny Muslims a proportionate role in the governance of that country, and some Arab Christian leaders have been outspokenly anti-Israel. That attitude was reflected in the opposition of Arab bishops to a Vatican Council declaration absolving Jews of collective responsibility for the death of Jesus...