Iraq is breaking apart. People are being slaughtered as the fundamentalist group ISIS seeks to carve out an Islamic caliphate over parts of Iraq and Syria.

Americans’ fingerprints are all over this crisis – we were the ones who upset the Iraqi apple cart 11 years ago – but our response to this development should be restrained and cautious. There is little to be gained and much to lose by taking the wrong steps.

It was never possible for the United States to guarantee permanent peace and stability in Iraq, even though our instigating role there placed a heavy burden on us. At some point, it was necessary for Americans to pull back from the optional war it launched and let Iraq govern and protect itself.

Only Iraq wasn’t interested. A fundamental flaw of our invasion was the belief that a democratic state could overcome the history of hostility among Sunnis, Shiites and Kurds. It couldn’t. The government of Prime Minister Nouri al-Maliki, a Shiite, refused to include the Sunni minority in any substantive role, just as dictator Saddam Hussein, a Sunni, excluded Shiites.

But now, the region is in upheaval. Syria is in the midst of a civil war that ISIS – standing for Islamic State of Iraq and Syria – is exploiting. Its assault on Iraqi cities was sudden and swift. The Iraqi military that the United States helped to train turned to pudding, unable or unwilling to resist the long-planned and devastating assault.

The question now is how – and if – the United States should respond. The good news is that President Obama has ruled out sending in American troops. That would constitute an unforgivable sacrifice of American blood, given what we have learned about the unlikelihood of imposing a democracy on Iraq, the ancient hostilities among the region’s religious factions and Iraq’s own unwillingness to help itself.

That doesn’t mean the United States has no interest in the outcome of the current crisis. It does, and not only because of the 4,500 American lives that were lost in the 2003 invasion and its 11-year aftermath. We also have an interest in Middle East stability – if such a concept is possible – given what we have learned about instability, statelessness and the opportunity those circumstances provide for terrorists.

Actions of the Obama administration are, so far, appropriate, including the decision to move the aircraft carrier USS George H.W. Bush and two other ships into the Persian Gulf and the possibility of using drones, and even – head-spinning though it is – cooperating politically with Iran. However, it’s difficult to see how the military can target strategically and what long-term benefit it can achieve, absent some agreement among the country’s warring sects.

The possibility of partnering in some way with Iran, meanwhile, goes further to underscore the dirty way war and politics are played in this part of the world. It’s the kind of thing that was necessary to secure the freedom of the captured American serviceman Bowe Bergdahl, and it may be necessary to stem a looming disaster in Iraq.

And if nothing works, there is still this: ISIS succeeds, and organizes what amounts to a new state in the Middle East – a brutal one, no doubt, but one more likely based on history than existing borders. They might, for a time, keep themselves violently busy in their own backyard.