President Donald Trump is challenging his Secretary of State Rex Tillerson to an IQ test. In a Forbes interview published on Tuesday, Trump characterized reports that Tillerson called him a “moron” as “fake news,” but said that if they were true they should compare intelligence tests.

“I think it’s fake news, but if he did that, I guess we’ll have to compare IQ tests,” Trump said. “And I can tell you who is going to win.”

Based on previous instances of Trump denigrating the IQ of adversaries, it seems as though he believes he would win.

The Washington Post cataloged several such instances in a piece published on Tuesday. They included:

Trump saying he has a higher IQ than George W. Bush and Barack Obama.

Trump saying his IQ is higher than TV host Jon Stewart’s.

Trump challenging the Mayor of London Sadiq Khan to an IQ test.

Trump repeatedly denigrating Rick Perry’s IQ and saying he should have been subject to an IQ test before being allowed to participate in a Republican primary debate.

As the Post noted, both Perry and Tillerson—whose IQs have now been called into question by the president—are part of a presidential Cabinet Trump has stated as fact is “the highest IQ of any Cabinet ever assembled.”

Those comments were made after Trump described then–Health and Human Services Secretary Tom Price as “smart.” Price resigned last month after wasting hundreds of thousands of taxpayer dollars on luxury airfare.

In a press conference earlier this month, Tillerson said the president “is smart” but did not deny calling him a “moron.” (A State Department spokesperson later denied that the secretary of state had called the president a “moron.”)

Trump had previously undercut his secretary of state by tweeting that he was “wasting his time” by negotiating with North Korea over their nuclear arsenal.

I told Rex Tillerson, our wonderful Secretary of State, that he is wasting his time trying to negotiate with Little Rocket Man... — Donald J. Trump (@realDonaldTrump) October 1, 2017

...Save your energy Rex, we'll do what has to be done! — Donald J. Trump (@realDonaldTrump) October 1, 2017

In the Forbes interview, Trump said that these statements describing Tillerson’s work as a waste of time did not undercut Tillerson’s work but strengthened it.

“I’m not undermining,” the president said. “I think I’m actually strengthening authority.”