"If Mr. Paul wants to be taken seriously he needs to do more than pull political stunts that fire up impressionable libertarian kids," McCain said. "I don't think what happened yesterday is helpful to the American people." 

Paul appeared to swipe back during his speech Thursday at CPAC, saying "the GOP of old has grown stale and moss-covered."

"Our party is encumbered by an inconsistent approach to freedom," Paul said.

On Friday, McCain brushed the criticism aside, acknowledging he was "the luckiest man."

"You know that yesterday was the 40th anniversary of my return from prison in Vietnam and I’ve had the most wonderful life that anyone could ever have," McCain said.

But asked more specifically about Paul's critique, McCain said their differences were emblematic of a foreign policy split within the Republican party — and invoked former President Reagan to argue that his approach was more appropriate.

"I  think we are now beginning to see a struggle, not so much between old people and newer people but whether we’re going to be the Ronald Reagan Republicans," McCain said. "Ronald Reagan best said, ‘Take down this wall.’ Ronald Reagan believed in peace through strength, and … we are on the way right now to a hallow military. The command down in the Marine Corps said a few days ago that half of his forces would be unable and not ready to deploy in the case of some kind of crisis. We are seeing that fight."

McCain also again swiped at Paul's critique of the nation's drone policies, saying the Kentucky lawmaker was voicing “not a rational argument” that “scares people.”