John McCain's Debate Advice for Donald Trump's Opponents

Republicans should resist the urge to gang up on Trump, he says.

"Do not ... not so much ignore something like a direct attack, you don't want to totally ignore him, but get your message out," he said.

McCain, a two-time presidential candidate and the Republican nominee in 2008, suggested the other Republicans resist the urge to try to corner Trump.

"If you gang up on Donald Trump, then obviously you're going to have sympathy for him," he said.

"I don't think there's any doubt that if he took 10 percent out of he Republican vote, that would be very, very difficult to overcome," McCain said.