With his fiery presence and inflammatory rhetoric, Donald Trump has had to fight off charges that he lacks the temperament to be president.

However, tech mogul Peter Thiel, who recently announced $1.25 million in donations to groups supporting the Republican, believes it's Democrat Hillary Clinton who poses the real threat.

"The kind place where I worry about the most on a policy level is, do we get into more wars or not?" Thiel said Monday during a speech at the National Press Club. "I'm not sure if that's more of a temperament or more a matter of world view, but certainly I would worry much more in that with Hillary getting us into wars."

Thiel actually believes Trump has mellowed some over the years and would be unlikely to make the kinds of comments today that he did a decade ago — such as the video where he made lewd remarks about women.

Trump has run into numerous other issues as well, with his critics accusing him of inciting political violence and mocking a disabled reporter.

"There are a lot of things that are beyond the pale," Thiel said. "There are things that Trump said a decade ago that even he would absolutely no longer say today."

He said he doesn't think Clinton would necessarily get the U.S. into a nuclear war with Russia, but her more aggressive approach to foreign policy still worries him.

"If you actually look at the specifics — where might something happen, where might something go wrong — I would think that in some ways Hillary is much more dangerous than Trump," Thiel said.