“The boots on the ground question is always the toughest one,” Zinni said. “I wish we were not so paranoid about boots on the ground. We can’t even define it! There’s going to have to be special operations forces,” even with air strikes.

“Very simply put, if you put two brigades on the ground of U.S. forces, they would push ISIS back to Syria in a heartbeat and probably take less time, less cost, and I think in the long run fewer casualties overall.”