Obama and Clinton represent different Democratic tendencies. In their descriptions of the current situation in Iraq, Clinton emphasizes that there cannot be inclusive politics unless the caliphate is seriously pushed back, while Obama argues that we will be unable to push back the caliphate unless the Iraqis themselves create inclusive politics. The Clinton language points toward some sort of intervention. Obama’s points away from it, though he may be forced by events into being more involved.
It will be fascinating to see how Clinton’s approach plays in Democratic primaries. (I’d bet she is going to get a more serious challenge than people now expect.) In practice, the Clinton approach strikes me as more sound, for the same reason that early intervention against cancer is safer than late-term surgery. In the Middle East, malevolent groups like the Islamic State in Iraq and Syria grow unless checked. Even in situations where our “friends” are dysfunctional, the world has to somehow check them, using a multitude of levers. Having done so little in Syria and Iraq for the past year, we can end the caliphate or we can stay out of Iraq, but we can’t do both.
If you don’t take steady, aggressive preventive action, of the sort that Clinton leans toward, then you end up compelled to take the sort of large risky action that Obama abhors.