The United States has been conducting hundreds of airstrikes against Islamic State targets in [Iraq] for the past month. In contrast to Syria, there are actual ground forces in Iraq with an interest in reclaiming territory. So, in many ways, Iraq is an easier test of the effect of U.S. air power on changing the balance of power on the ground. And yet, according to The New York Times's David Kirkpatrick and Omar Al-Jawoshy, things haven't changed all that much in Iraq: "After six weeks of American airstrikes, the Iraqi government's forces have scarcely budged the Sunni extremists of the Islamic State from their hold on more than a quarter of the country." Given that it will be months before the Free Syrian Army receives any training, the evidence from the Iraq campaign does not bode well for any immediate success in Syria.
Daniel Larison offers a forecast:
Obama has embarked on a military campaign that will consume and thoroughly discredit the remaining years of his presidency. I suspect that the public will sooner or later sour on a war that was originally sold as a brief and limited operation, and their support for an air campaign will wane as it becomes apparent that the war cannot achieve its stated goal. Even if that doesn't happen, Obama will still be responsible for committing the U.S. to exactly the sort of unnecessary and open-ended war that he was expected to oppose.