Talk show pioneer David Letterman, in a wide-ranging 90-minute conversation onstage at the New Yorker Festival tonight, said his old guest and sparring partner Donald Trump is not only a racist, but a “badly damaged human being.”

“God bless Trumpy,” Letterman joked when asked by New Yorker articles editor Susan Morrison if he missed having an outlet for his topical barbs. “While it might be fun here and there to drop something in, I don’t know if I’d have the stamina for a full plate of Trumpy night in and night out.”

Letterman (pictured above at an appearance last May) then went on to recount the tale of how he came to call Trump – a frequent guest on both NBC’s Late Night and CBS’s Late Show – a racist on air, and how Trump responded off camera.

Photo by Charles Sykes/Invision/AP

“Donald Trump (pictured at left following a Late Show appearance) was a fixture on our show,” Letterman said. “He was a beloved guest – people got excited, I think it was the allure or the pose of being a millionaire, and the hair. I used to make fun of his hair. I used to refer to him as a slumlord. We got to love having Trumpy on because he could really take a punch. I was asking him about being married to Marla Maples and he said, ‘If you’re interested I’ll give you her phone number.’

“Then he started messing around with the birthers, and how did a guy like (Barack Obama) get into Columbia, how did a guy like him get into Harvard, and I started thinking..break down the innuendo about that. We started talking about it one night on the show, without Trumpy, and I said, Well, maybe if he’s a racist we shouldn’t invite him on the show.

“So then I had to call Don because he said he wasn’t coming back on the show, and I said Don I don’t think you’re a racist because you’re too smart. I don’t think smart people are racists, and he said, Well of course I’m smart and I’m not a racist, and I said there you go, you’ve proven my point, come back and be on the show. And he came back and did the show two or three times after that and I thought the deal was done. I’d called him out and said he’s too smart to be a racist. Well, I was wrong.”

Letterman, who acknowledged being flattered by the Hillary Clinton campaign ad featuring an old Late Show bit in which he confronts Trump with various Trump neckties and products made in China, said he initially and mistakenly believed that Trump’s bid for the Presidency would be finished with the candidate’s talk of “evil people coming from Mexico.”

But, the retired host continued, the worst was ahead. “The thing that I found unconscionable, actually unconscionable, is that he physically mocked a man who is a reporter for The New York Times and has, I believe, a physical birth defect. And I just thought, forget he’s Donald Trump, forget he’s running for president, forget who he is, forget what he is. If you can, in a national forum, with great confidence stand there and make fun of someone suffering a disability over which they have had no control all their entire life, then you are a badly damaged human being.”

Letterman appeared confident that his old walking punchline won’t make it to the White House. “I said when this began, this problem will solve itself. I firmly believe that. Perhaps there are Trump supporters in the house…please don’t take any offense at this, but there’s not a chance in hell that this man will be elected president.

“And if he is I’ll get you all a lovely gift from Tiffanys.”