From a reader:

Jonah,
The argument that the US has to stay in Iraq to avoid a genocide is not just a moral one. Our strongest allies in the region – Jordan, Egypt, the GCC states – are all primarily Sunni. If they see us turning our back as a betrayal, it could damage those relationships permanently. We must stay then, not just for the Iraqis, but for cold, hard geopolitical reasons that should appeal to the realpolitik demanded by Derb.

Again, I agree entirely with this. My main motives for staying aren’t the moral concerns involved with genocide. I think being perceived as the loser in a war like this will be very bad for America, as would the chaos that would possibly ensue in the region. But the moral arguments dovetail the realpolitik arguments. But for those who usually consider genocide — or ethnic cleansing if you prefer — a sufficient justification for intervention, that precondition will almost surely be created by our departure. And yet, they don’t care.