Jeb Bush and Donald Trump got into another heated exchange — this time a battle of strength stemming from their views on immigration reform.

“The weakest person on this stage, by far, on illegal immigration is Jeb Bush. ’They come out of an act of love,’” Trump said, quoting something the former Florida governor said last year about why undocumented immigrants come to the U.S. “Whether you like it or not, he is so weak on illegal immigration it’s laughable, and everybody knows.”

Bush labeled Trump’s attacks “standard operating procedure” from the billionaire businessman. “If you wanna talk about weakness — you wanna talk about weakness,” Bush began, “it’s weak to disparage women.”

“No it’s not,” Trump interrupted.

“It’s weak to disparage Hispanics,” Bush continued, with Trump butting in, “I don’t think so.”

“It’s weak to denigrate the disabled, and it’s really weak to call John McCain a loser because he was…that is outrageous,” Bush said. “That is an American hero.”

Trump started to say he never called McCain a loser but began ridiculing Bush for being critical of his language on the campaign trail. “Two days ago he said he would take his pants off and moon everybody and that’s fine. Nobody reports that,” Trump said. “He gets up and says that, and then he tells me oh, my language was a little bit rough. My language. Give me a break.”