NEW YORK — Stephen Colbert showered thanks on Donald Trump, his “Late Show” guest.

“I want to thank you not only for being here but for running for president,” Colbert told the GOP frontrunner Tuesday night. “I’m not going to say this stuff writes itself, but you certainly do deliver it on time every day.”

Colbert’s gratitude for Trump’s comic assistance was well-placed. Peppering Trump with questions and wisecracks during his appearance, the CBS host reduced the usually domineering Trump to straight-man status, an unaccustomed role Trump performed with rare grace.

Bringing up Trump’s proposal to build a wall between the United States and Mexico, Colbert offered his own mocking version of a way to bar illegal immigration: Two walls, and in between them a moat filled with fire and fireproof crocodiles. “Is that enough?” Colbert asked.

And focusing on Trump’s insistence that Mexico would pay for the wall, Colbert drew him into a role-playing exercise – a phone call where “you’re you, and I’m the president of Mexico.”

Colbert noted that Trump is leading the field while he vows to finance his campaign out of his own pocket.

“The Republican Party has been a big pusher of the idea that money is speech, and you’re a $10 billion mouth,” said Colbert. “You’re their worst nightmare.”

“I think the establishment in the Republican Party probably isn’t that thrilled,” he agreed.

Trump repeated his contention, as a former heavy campaign donor, that candidates who accept major contributions are typically “owned” by those donors once in office.

“You gave them a big contribution and you want something and all of a sudden they’ve very receptive,” he said. If you didn’t make a healthy gift, “believe me, you get the cold shoulder.”

Colbert asked if Trump really wants to be president: “If you actually got the gig, would that be a step down for you? You know what the pay is like, right?”