“I just don’t think Marco Rubio’s going to be able to slime his way to the White House,” Christie said. “He wants to put out a whole bunch of negative ads? Go ahead. I hope that he will acknowledge at some point that I couldn’t care less.”

Christie mocked Rubio as naive in the arts of political street-fighting — “He’s never been in a tough race in his life,” he said dismissively — and tore into Rubio’s work in the so-called Gang of Eight on a 2013 immigration bill that has since become anathema to conservatives.

“The guy who advocated for amnesty and then ran away when the topic got too hot tells you two things: He’s not a reliable conservative, A, and B, whenever it gets too hot, Marco turns tail and runs,” he said. “I’m not the least bit concerned that Marco Rubio will hurt me with conservatives. Marco Rubio has work himself to do with conservatives.”