"No, of course not," Cruz responded.
Colbert pressed him on whether he could consider compromising and working with Democrats, as Reagan did, without feeling like he had "capitulated with the devil." Cruz didn't exactly embrace bipartisanship, but conceded that there is "nothing diabolical" about the other side.
Colbert found himself defending Cruz when the conversation turned to same-sex marriage and the audience began booing Cruz's responses.
"Guys, however you feel, he's my guest so please don't boo him," Colbert told his audience.
"Let's be precise: Under the Constitution marriage is a question for the states," Cruz said. He defended his stance that the 10th Amendment gives only states the right to weigh in on the issue.
He also had a request for businessman and fellow Republican presidential candidate Donald Trump, who will appear on the show Tuesday evening.
"I like Donald a lot and if you could, ask him if he could possibly consider donating $1 billion to our campaign," he said.