In an interview with ABC News' Jonathan Karl on his charter plane to South Carolina, Marco Rubio said that he had made the decision at last Saturday's debate not to attack Republicans, but that "in hindsight, maybe that was a mistake."
"I shouldn’t have done it that way because what it did was it moved me to a message that pivoted away from the question and gave this perception that I tried to evade it," Rubio told Karl Wednesday afternoon. "The truth is, I just didn’t want to get into a Republican-on-Republican fight but in hindsight that probably wasn’t the best way to approach it."
Rubio placed fifth in the New Hampshire primary, according to the AP. He acknowledged that his debate performance "didn't help" him win supporters in the state.
"It’s disappointing because I know we could have done better and I believe we would have done better had it not been for a poor 90-second moment in the debate on Saturday," Rubio said.
Rubio continued: "But you got put that move forward. You can’t change the past. All you can do is influence the future. And that’s what I’m focusing on. In the future, if there’s a conflict at a debate, you’re going to have to engage likewise on what’s happening."
Rubio then pivoted to GOP front-runner Donald Trump.
"[Trump] is now clearly the frontrunner for the Republican nomination," he said. "So Donald has to begin to outline clear ideas on issues like national security and foreign policy and the economy. It’s no longer enough to continue to say the great things you’re going to do, but you won’t tell us how you’re going to do them."
He said he agreed that the longer Jeb Bush -- and others -- stay in the race, the more likely Trump wins the nomination.
Rubio said he's confident he will win the Republican nomination and be back on the New Hampshire ballot in the general election.