President Donald Trump on Monday thanked former Senate Democrat leader Harry Reid for affirming his genius.

“Former Democrat Senator Harry Reid just stated that Donald Trump is very smart, much more popular than people think, is underestimated, and will be hard to beat in the 2020 Election,” Trump wrote on Twitter. “Thank you Harry, I agree!”

In an interview with CNN contributor David Axelrod, Reid admitted he used to think Trump was “not too smart” but had since changed his mind.

“I don’t think he’s intellectually a powerhouse but he is basically a very, very smart man,” he said. “No matter what the subject, any argument he involves himself in, it’s on his terms. You’re always arguing against him.”

Reid warned Democrats not to underestimate President Trump in the 2020 election.

“Anyone that thinks Trump’s going to be beaten easily should have another thing coming,” he said in the interview.

Reid said Trump would always have 40 percent approval, despite doing things that troubled moderates and infuriated Democrats.

“I repeat, he is not going to be beaten easily,” he said. “It’s going to take a campaign of wisdom and patience, but he is beatable for sure.”