As a parade of top Pentagon leaders publicly urged caution about military intervention in Libya, Sen. John McCain, R-Ariz., shot down any suggestion that the U.S. couldn't afford to enforce a no-fly zone over Libya.

"We are spending over $500 billion dollars, not counting Iraq and Afghanistan, on our nation's defense. Don't tell me we can't do a no fly zone over Tripoli," the ranking member of the Senate Armed Services said at the Atlantic Council Tuesday evening.

"I love the military, I love it, it's been my life, but they always seem to find reasons why you can't do something rather than why you can," Sen. McCain said.

At a news conference with Chairman of the Joint Chiefs of Staff Adm. Mke Mullen, Defense Secretary Robert Gates said the military would be providing the president with the "full range" of options regarding intervention in Libya, but went out of his way to suggest the United States couldn't afford another war.

"We also have to think about the use of the U.S. military in other countries in the Middle East," Gates said.

The Senate unanimously approved a non-binding resolution on Tuesday night calling for the United Nations Security Council to impose a no-fly zone over Libya. It's been reported that Anti-Qaddafi troops are seriously debating whether to request U.N.-backed airstrikes.

Asked directly about the possibility of a no-fly zone, Gates told reporters, "There is no unanimity within NATO for the use of armed force, and the kinds of options that have been talked about in the press and elsewhere also have their own consequences and second and third order effects so they need to be considered very carefully."

"You would have to remove the air defense capability in order to establish the no-fly zone," Commander of U.S. Central Command, General James Mattis, said to Sen. McCain at a hearing held by the Senate Armed Services Committee "No illusions here. It would be a military operation. It wouldn't be just telling people not to fly airplanes."

Tuesday evening, Sen. McCain insisted the United States had the upper hand in Libya. "Once we announce a no fly zone, most of those Libya pilots wouldn't fly."

On Libyan leader Qaddafi, McCain said, "This guy's days are numbered. The question is -- is can we shorten those number of days to save lives, to save people's lives because it's clear he's going to kill whoever he thinks he can in order to stay in power."