The backlash to the Kurdish referendum is escalating dangerously:

The Iraqi army launched an operation to retake Kurdish-held positions around the disputed oil city of Kirkuk on Friday amid a bitter row with the Kurds over a vote for independence last month.

A senior Kurdish official said thousands of heavily armed fighters had been deployed to resist the offensive “at any cost” and called for international intervention with the federal government in Baghdad to prevent the confrontation worsening.

The danger of holding the referendum was that it would be the trigger for a new round of armed conflict. Including Kirkuk in the referendum made that outcome more likely. Unfortunately, one of the worse scenarios that we feared might happen is beginning to unfold. There might still be a chance to persuade the Iraqi government and Kurdish leadership to stop this conflict before too much damage is done, but I fear that all sides are now so entrenched in their positions that none of them is willing to consider backing down. If fighting begins at Kirkuk, it could very well provoke a Kurdish declaration of independence. That would likely cause Turkish and Iranian intervention to one degree or another. Given the horrible state of U.S.-Turkish relations at the moment, Washington is in no position to rein Turkey in, and it’s doubtful that the U.S. would be able to do so even if the relationship with Ankara wasn’t in tatters right now.

The U.S. should offer mediation to help prevent the conflict from escalating into a larger conflagration, but it absolutely must not let itself get dragged in to the fighting on either side. There will probably be significant pressure on the administration to “do something” in response to the conflict, but that needs to be resisted as much as possible.