There are signs that many of the President’s advisors share a belief that the rise of ISIS is as frightening to the mullahs as it is to the West, and that the new jihadi peril will therefore strengthen the factions in Iran who believe in compromise with the West. They will see Iran’s willingness to accept Abadi as evidence that much broader cooperation is possible, and they will urge President Obama to do everything he can to seize the opportunity for a breakthrough with Iran. U.S. negotiators will sweat blood to meet the new November deadline in talks with Tehran, in Iraq the Administration will seek to build on common support for Abadi, and militarily we may even look for ways to cooperate with Iran against ISIS.

More, the perception that a breakthrough with Iran is just around the corner will encourage the President to slight or sacrifice the interests of traditional U.S. allies in the region. It will strengthen the hand of those in the Administration who tell the President that he should stay the course in the Middle East, pursuing a ‘grand bargain’ with Iran, and supporting ‘moderate Islamists’ and pro-Muslim Brotherhood governments in places like Qatar and Turkey, even if that alienates Saudi Arabia, Israel and Egypt.

If America takes this course, expect regional tensions to rise, rather than relax, even if things calm down in Baghdad. It’s not clear that the President’s goal of a grand bargain with Iran is within reach, or that it will deliver the kind of stability he hopes for. For one thing, it’s possible that the Iranians are less interested in reaching a pragmatic and mutually beneficial relationship with Washington than in using Obama’s hunger for a transformative and redeeming diplomatic success to lure him onto a risky and ultimately disastrous course.