Won’t a contested convention require more of a campaign than après moi, le déluge? “I have an organization but it’s largely myself,” he said.

More heavyweights are jumping in to stomp Trump, including Elizabeth Warren. Asked about her jabs, he pounced: “I think it’s wonderful because the Indians can now partake in the future of the country. She’s got about as much Indian blood as I have. Her whole life was based on a fraud. She got into Harvard and all that because she said she was a minority.”

Told that President Obama was mocking his wine as $5 wine marked up to $50, Trump shot back, “My wine has gone through the roof.”

What about Mitt Romney, who’s pushing for an open convention? “He’s a jealous fool and not a bright person,” Trump said. “He’s good looking. Other than that, he’s got nothing.”

Paul Ryan, who will be leading the G.O.P. convention in Cleveland, says there could be a floor fight. But he protested that he would, no, no, never take it himself, just as he once said about the speakership.

Ryan snickered at the idea that Mexico would pay for the wall and chided Trump for warning that there would be riots at the convention if the Gasping Old Party tried to snatch the nomination. Was the speaker interested in seizing the crown himself?

“I don’t think so,” Trump said, noting that he liked Ryan and that they’d talked. “All that matters is the votes. I see people making statements about me that are harsh and yet they are calling me on the other line saying, ‘Hey, when can we get together?’”