"We are the lead nation in the world, and America matters and we must lead," McCain added. "Sometimes that leadership entails sacrifice sadly."
With President Barack Obama's July deadline to begin troop withdrawal in Afghanistan approaching, McCain said the U.S. cannot give up recent gains through a swift withdrawal, saying he would support a "modest withdrawal" of five to ten thousand support troops in the coming months.
"We abandoned Afghanistan once and we paid a very heavy price for it in the attacks of 9/11," McCain said. "We do need to move into the eastern Afghanistan and finish this fight with one more season."
At last Monday's GOP debate, Republican frontrunner Mitt Romney said, "It's time for us to bring our troops home as soon as we possibly can consistent with the word that comes from our generals that we can hand the country over…" He added, however, that he believed the U.S. has "learned some important lessons" from Afghanistan.
"We've learned that our troops shouldn't off and try and fight a war of independence for another nation," Romney said at the debate. "Only the Afghanis can win Afghanistan's independence from the Taliban."
McCain disputed Romney's depiction of the war, saying, "I had never heard it described that way," adding that the U.S. military efforts should be allowed to fully succeed.
"I wish that candidate Romney and all the others would sit down with General Petraeus and understand how this counterinsurgency is working and succeeding," McCain said. "For us to abandon Afghanistan to the tender mercies of the Taliban and radical Islamic extremists, I think would be repeating mistakes we made before."
McCain even offered some political advice to President Obama, saying continued success in Afghanistan in the next year would allow for more substantial withdrawals next summer during the 2012 election year.
"Suppose the surge continues to succeed and the summer of 2012 the president was able then to announce a massive withdrawal? That would be very helpful to the president politically," McCain said. "I always try to help him as much as I can politically."