Juan Cole argues that partition is not a solution to the unfolding disaster in Iraq. He argues that since Iraq's ethnic and religious divisions are not neatly geographically divided, any attempt to draw new borders would merely make the designation of those borders a new casus belli.
Then again, maybe the U.S. will "pull a Balkan," and facilitate regional ethnic cleansing in Iraq the same way it allowed Croatia to displace a couple hundred thousand Serbs from the Krajina in August 1995 (and four years later helped the ethnic Albanians in Kosovo to do something similar). The unpleasant truth, which no one except the Israeli settler movement likes to say out loud, is that ethnic cleansing works -- if by "work" we mean resolve claims over the division of territory between competing ethnic groups.
However, Cole is right that the situation in Iraq is made more complicated by the fact that partition would almost certainly drive the Sunni Arabs into the arms of al-Qaeda in large numbers. And notes, ominously, that "Some Iraqi guerrillas are already talking about hitting back at the US mainland." It's one thing to create resentful Serbs; it's another to create resentful Islamic fanatics.
Then again, we're already doing that....