Chris Wallace was joined on "Fox News Sunday" by top Middle East experts to discuss the situation on the ground and President Obama's policies.

Gen. Jack Keane (Ret.) said the spread of radical Islam is the greatest security challenge the U.S. has faced since post-World War II, with the rise of the U.S.S.R. and communism.

Ambassador Dennis Ross said the Obama administration's approach to ISIS has a fundamental problem.

"You cannot defeat ISIS in Iraq unless, in fact, you deal with the problem of Syria," Ross said. "If you're only attacking the ISIS targets in Syria and allowing Assad to attack the non-ISIS targets, you're creating a problem for yourself. You're going to have to resolve that contradiction if you want a strategy that's effective."

Sen. Kelly Ayotte (R-NH) said a major problem is that the administration refuses to use the words "radical Islam."

"You have to define your enemy ... I think they should spend less time on being worried about being politically correct, about how we define our enemies, and more time on a strategy to defeat them," Ayotte said.

Watch more from the "Fox News Sunday" panel above.