Writing in Wednesday's Washington Post, Joe Biden warned that unless we get things right in Iraq, "violence might escalate into a full-blown civil war." It used to be that we had to stay in Iraq in order to avoid a civil war; now it's a full-blown civil war that our presence is preventing. (A recent Daily Telegraph article worries about a "full-scale civil war.") The status quo, then would seem to be a partially inflated civil war, or maybe a miniature-scale one.

A look at the operation in Tal Afar -- in which the United States took the town, absurdly, for the third time -- the weekend before Biden's op-ed suggests that civil war is well on its way to being full-blown. Tal Afar is inhabited mainly by members of Iraq's small Turkmen community, the people of which speak a language similar to Turkish and enjoy good relations with Turkey. Turkey, famously, enjoys poor relations with its own Kurdish minority as well as with the newly empowered Kurdish minority in northern Iraq. Most Iraqi Turkmen live within the sphere of Iraq that local Kurds want to turn into a highly autonomous -- if not outright independent -- Kurdistan. Iraqi Turkmen, sensibly, would rather be one minority group among many in a largely unitary, pluralistic Iraq than a disenfranchised minority inside a largely monolithic Kurdistan.

Meanwhile, most Turkmen -- including those in Tal Afar -- are Sunni Muslims, though a minority follow the Shia faith. Sunni Turkmen largely sympathize with the insurgency, and, as a result, the town has repeatedly become an insurgent stronghold and apparently plays an important role as a way station for foreign fighters infiltrating from across the Syrian border. Thus, American troops, operating under orders from the Shia-dominated central government and backed by Iraqi-army troops who turn out to be relabeled Kurdish militiamen, attacked the city. Working with them to provide intelligence were a group of Shia Turkmen. According to The Washington Post, in the wake of the attack, detentions of Sunni Turkmen have frequently been undertaken "solely on the hearsay" of these Shia informants who may or may not know what they're talking about and may or may not simply be settling old scores.

The forces loyal to insurgent leader Abu Musab al-Zarqawi had largely already left the city. But for now, at least, the Kurdish-Shia coalition retains control over the city.

Following these events, a voice recording thought to be from al-Zarqawi was released, proclaiming, "The al-Qaeda organization in the Land of the Two Rivers [Iraq] is declaring all-out war on the Rafidha [a pejorative term for the Shia], wherever they are in Iraq," and argued that "as for the government, servants of the crusaders headed by Ibrahim al-Jafari, they have declared a war on Sunnis in Tal Afar." In the days that followed, insurgents unleashed a massive wave of violence, including terrorist attacks against Shia civilians and bomb assaults on American forces and security services loyal to the Iraqi government.

This, in other words, is the civil war, an event presaged last fall by fighting in the ethnically mixed city of Mosul. Shia and Kurds, backed by the United States, are fighting Sunnis. Whatever justification may exist for indefinitely prolonging the American presence in Iraq, it must be seen that this is what we're doing -- helping our preferred side to win a civil war, not preventing one from breaking out.

Americans need to ask themselves at least two questions about this state of affairs: Is it wise, and is it moral? On wisdom, it's well-known that the United States has something of an al-Qaeda problem. We're afflicted by a global jihad movement that likes to portray itself as merely defending the interests of Sunni Muslims against a hostile "crusader" coalition directed from Washington. Deploying American troops on the Shia side of a Sunni-Shia civil war is much more likely to enhance, rather than reduce, the appeal of that message. On morality, proponents of an indefinite military commitment have done a good job of seizing the high ground of responsibility and idealism, but must be forced to confront the reality of what's happening. Ethnic and sectarian conflicts are legendarily ugly affairs. The Iraqi political forces with which we've aligned ourselves have no record of commitment to democracy, liberalism, human rights, or any of the other high ideals under whose banner our troops are operating. A desire, no matter how strongly or sincerely held, to make it the case that we are fighting for those things will not make it so.

Matthew Yglesias is a Prospect staff writer.