Five things that could go horribly wrong with Obama's action in Iraq

2: The ground war is a dud

Nobody believes the U.S. can defeat the Islamic State with air power alone. A real victory over the Islamic State, the thinking goes, will be won with a ground war, supported by a overwhelmingly American air campaign. Without U.S. combat troops, the war will be fought by non-American boots on the ground — mostly Kurds and the notoriously unreliable Iraqi army, as well as, in Syria, some of the opposition forces the president once mocked as ineffective. Together, their performance will determine the outcome of the fight.

“The ground campaign is what is going to defeat ISIS in the end,” said retired Gen. Jack Keane, a former Army Vice Chief of Staff, on Fox News Wednesday night. “In that ground campaign, we are totally dependent on surrogate forces. Whether we can do this or not, nobody knows.”

“His plan is predicated on more U.S. assistance to equip Iraqi and Kurdish ground forces, and Syrian rebels, to take the fight to ISIS,” added William Inboden, a former top official on the Bush National Security Council, in response to an email question. “What if Iraqi and Kurdish forces fail to step up and suffer repeated defeats by ISIS? U.S. airpower alone almost certainly won’t be sufficient to ‘destroy’ ISIS. If the Iraqi and Kurdish forces and Syrian rebels aren’t up to the task, and ISIS continues to grow in strength, is Obama prepared to send in U.S. ground forces?”