Harry Reid has changed his mind about President Donald Trump. The former Senate majority leader hasn’t decided to support the man, but he now sees him as a smart opponent, warning fellow Democrats that they must do the same if they want a chance at victory in 2020.

“I used to think that Donald Trump was not too smart. I certainly don’t believe that anymore,” Reid told “Axe Files” host David Axelrod in an interview that will air Saturday evening on CNN.

During the presidential election between Trump and Hillary Clinton, Reid called Trump a “spoiled brat” and a “human leech who will bleed the country.”

Reid, who retired in 2017, says Trump’s brilliance is that any debate with him is done “on his terms.”

“I don’t think he’s, intellectually, a powerhouse but he is basically a very, very smart man. No matter what the subject, any argument he involves himself in, it’s on his terms. You’re always arguing against him. He never, never, is willing to debate an issue on terms that aren’t his,” Reid says.

As for advice he would give to the 2020 Democrat who will face off against the president, Reid warns: “Anyone that thinks Trump’s going to be beaten easily should have another thing coming.”

On #AxeFiles airing Saturday on @CNN, former @SenatorReid warns Dems about @realDonaldTrump & 2020:

“I used to think that Donald Trump was not too smart. I certainly don’t believe that anymore. No matter what the subject, any argument he involves himself in, it’s on his terms. pic.twitter.com/y9seGhuAHV — David Axelrod (@davidaxelrod) October 11, 2019

Touching on the impeachment inquiry into Trump and the current state of the Senate in his upcoming interview, Reid said he believes Trump did something illegal in his phone call with the Ukraine president, a belief the transcript of the call disproves.

“All you have to do is have a basic understanding of what the law in America: You can’t do what he did and go unpunished,” Reid says, adding that the “evidence is very clear” that Trump withheld foreign aid from Ukraine, something of which there is no proof — there is even more evidence that Joe Biden may have actually done this when he was vice president.

As for the current state of the Senate, his harshest words are for Republicans unwilling to go up against the president.

“And we have these Republicans who are afraid to speak out against things that he does that are absolutely wrong and they know they’re wrong,” Reid says. “The only person we’ve gotten to say anything is Mitt Romney, and [Ben] Sasse has said something out of Nebraska. Other than that, they don’t say anything.”

Reid also singles out Lindsey Graham for his support of Trump.

On #AxeFiles, @SenatorReid spoke about @LindseyGrahamSC: “It’s amazing what happened to him when John McCain died. He suddenly was no longer a John McCain Republican. He became a South-Carolina-want-to-get-reelected Republican and he is a total fetch guy for the President.” pic.twitter.com/zwHHpdOLp8 — David Axelrod (@davidaxelrod) October 10, 2019

“It’s amazing what happened to him when John McCain died,” Reid says of the South Carolina senator. “He suddenly was no longer a John McCain Republican. He became a South-Carolina-I-want-to-get-reelected Republican, and he is a tote-and-fetch guy for the President.”

“I had such admiration for him. I’m so disappointed in what has happened to him. His whole personality has changed since John passed,” he adds about Graham.

Though Graham is a supporter of the president, he still makes it clear when he’s disagreeing with the man, like the recent announcement that Trump was moving troops out of regions of Syria and allowing Turkey to launch a military campaign there.