Dan Quayle shows support for Donald Trump on TODAY Show: 'He can win'

Former Vice President Dan Quayle said presumptive Republican presidential candidate

Donald Trump has his full support and expects others in the party will follow suit, including House Speaker Paul Ryan.

"I've been a Republican all my life, I'm going to support the nominee," he said Thursday in an exclusive TODAY interview. "I predict that most people in my position, or people that have been in the Republican Party in a long time, will rally around the nominee."

Quayle, whose own qualifications to serve in high office once were questioned by the general public, said he believes Trump "has the capability" and instincts to be president.

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"He's a winner. He's unusual. He's obviously very different, he's not going to play by the rules. It's a different situation, but I think that he can win," he said.

Quayle served as vice president under George H.W. Bush from 1989 to 1993. Both Bush and his son, former President George W. Bush, said recently through their spokesmen that they do not plan to endorse Trump.

See more of Dan Quayle through the years:

Quayle said he found it amusing that Republicans know who their nominee is far before Democrats do, although he said he believes Hillary Clinton will ultimately be the candidate running against Trump.

"On paper, you'd say, 'Well, she's more qualified.' But you know what? He's more qualified in the sense that the American people, I think, want an outsider," he said. "They want an outsider this time. She is not an outsider, so if you're looking for an outsider, no she's not qualified and he is."

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Asked who he thinks Trump should choose as his running mate, Quayle immediately suggested U. S. Sen. Rob Portman of Ohio.

"He'd be a great choice. Man of stature, substance," he said. "You pick him, you'd say, 'That's the way he's going to govern.' Rob Portman."