Rush Limbaugh. Bill Pugliano/ Getty Images Conservative radio talk show host Rush Limbaugh on Thursday noted the irony in Donald Trump being the person to persuade the Republican base into supporting amnesty.

"Could you imagine what it's like to be Jeb Bush today? Who knew?" Limbaugh said, pausing to laugh.

Limbaugh continued, according to a transcript on his website:

"Who knew — I'm sorry, folks. 'She's a bigot!' Who knew. First they tried Marco Rubio. They tried the Gang of Eight. They tried Jeb Bush. They tried any number of people to convince — they tried me! They sent emissaries to the EIB Network Southern Command. They tried everybody they could think of to try to convince the Republican base to support some form of amnesty for illegal immigrants. ...

"Let me regain my composure. Who knew that it would be Donald Trump to come out and convert the GOP base to supporting amnesty the same week Ann Coulter's book comes out. Poor Ann. Oh, my God, she's got this book, 'In Trump We Trust,' and in it she says the only thing, the only thing that could cause Trump any trouble whatsoever is if he flip-flops on abortion or on immigration, goes amnesty. It looks like he's getting close to it, and she's just beside herself with this. I mean, what timing."

Trump softened his position on immigration considerably this week, seeming to abandon his long-held belief that it was necessary to deport the millions of people living in the US without permission.

Limbaugh said he did not believe the shift in position would hurt Trump with his fans.

"Will this cause a problem with Trump supporters? I've done an informal survey here, and apparently it won't," the conservative talk show host said.

He added: "That's why I say who knew that it would be Donald Trump to come along and convert the GOP base to supporting amnesty? I don't see a lot of people preparing to abandon Trump over this. Maybe Coulter. Who knows what she's gonna do. I mean, her book hits, and it's just had the rug pulled out from under it."

Coulter, a best-selling conservative author, appeared to mock Trump on Twitter late Wednesday night for moderating his position on immigration.