America's top military officer wouldn't rule the possibility today of U.S. forces firing on Israeli jets, if Israel launched a pre-emptive strike on Iran.

In a town hall on the campus of the University of West Virginia, a young Air Force ROTC cadet asked Chairman of the Joint Chiefs of Staff Adm. Mike Mullen to respond to a "rumor." If Israel decided to attack Iran, the speculation went, those jets would need to fly through Iraqi airspace to reach their targets. That airspace is considered a "no-fly" zone by the American military. So might U.S. troops shoot down the Israeli jets, the airmen asked the chairman, if they breached that airspace?

Mullen tried to sidestep the question. "We have an exceptionally strong relationship with Israel. I've spent a lot of time with my counterpart in Israel. So we also have a very clear understanding of where we are. And beyond that, I just wouldn't get into the speculation of what might happen and who might do what. I don't think it serves a purpose, frankly," he said. "I am hopeful that this will be resolved in a way where we never have to answer a question like that."