David Letterman arrives at a Nordic State Dinner in May 2016. (Alex Wong/Getty Images)

David Letterman has been off the “Late Show” for nearly two years, and during that time he has apparently been bursting to offer his opinion on a few topics, especially his old friend “Trumpy.” He got the chance with a wide-ranging New York Magazine interview, during which Letterman talked — and talked and talked — about everything from the president’s Twitter habits to Jimmy Fallon’s infamous hair-mussing interview to the line of questioning he would use on President Trump if he had the chance.

The former late-night host, who’s still sporting that impressively bushy retirement beard, had a lot to say.

“I’m afraid something has happened to me hormonally,” he explained. “I can’t stop talking.”

Letterman and the president have some history, given that Trump was on Letterman’s show a number of times, and the late-night host loved to needle the businessman.

During one interview in 2012, Letterman put Trump in the hot seat by pointing out that a lot of Trump brand clothing is made in China — a country Trump had just been complaining about, saying it would inevitably surpass the United States as the world economic leader. The clip made it into a Hillary Clinton campaign ad.

No one should have expected Jimmy Fallon to go tough on Trump. That was Letterman’s job.

In the New York interview, Letterman talked about how he shied away from politics during his early years. He was taking a cue from Johnny Carson, the “Tonight Show” host who vowed never to talk about Vietnam, he explained. But then Jon Stewart came along.

“He made it so that not doing political stuff got to be the elephant in the room,” Letterman said. Around the same time, politics were becoming low-hanging fruit for comedians, especially with the revelations about Monica Lewinsky and President Bill Clinton.

David Letterman taught us to ward off celebrity stupidity. But stupidity won.

These days, Letterman thinks late-night hosts have an obligation to take on Trump, though he didn’t go so far as to throw the current “Tonight Show” host under the bus.

“I don’t want to criticize Jimmy Fallon, but I can only tell you what I would have done in that situation: I would have gone to work on Trump,” Letterman said.

How so?

“I would just start with a list,” he said. “‘You did this. You did that. Don’t you feel stupid for having done that, Don? And who’s this goon Steve Bannon, and why do you want a white supremacist as one of your advisers? Come on, Don, we both know you’re lying. Now, stop it.’”

Added Letterman: “I think I would be in the position to give him a bit of a scolding and he would have to sit there and take it. Yeah, I would like an hour with Donald Trump; an hour and a half.”

The comedian was particularly irked by the way the president attacked civil rights activist Rep. John Lewis on Twitter.

In feud with John Lewis, Donald Trump attacked ‘one of the most respected people in America’

“In addition to every other thing that’s wrong with the Trump, he’s ignorant in a way that’s insulting to the office, insulting to America, insulting to human rights, insulting to civil rights, insulting to John Lewis,” Letterman rattled off. “Trump saying that broke my heart. I thought, ‘You stupid son of a b—-. You ought to have known better than that.’”

Letterman may be fired up, but fans shouldn’t get their hopes up for a return to television. The former host insists he doesn’t have any interest in returning to late night. Besides, Seth Meyers and Stephen Colbert are doing the work of speaking truth to power. Not that Letterman would know. He doesn’t even watch any of the shows.

After 30 years in the business, he’s just over it. Plus, he admitted, “the truth is I can’t stay up that late.”

President Trump's first address to Congress was met with jokes from comedians Stephen Colbert, Trevor Noah and others. (Video: The Washington Post)