Marco Rubio once routinely referred to Republican rival Donald Trump as a "con man." But Trump's still "substantially better" than Democrat Hillary Clinton, Rubio told Florida reporters Thursday.
"I'm going to support him. I'm going to vote for him," he said.
In a separate interview, Rubio told CNN's Jake Tapper he'd be willing to speak on Trump's behalf at the GOP nominating convention in Cleveland.
The Florida U.S. senator said in the sit-down with Florida reporters that he has more faith in Trump than Clinton on a variety of issues, from overturning the Affordable Care Act to opposing abortion to appointing strict constructionists to the Supreme Court.
"Donald Trump won. Donald Trump was not a default choice," said Rubio, whose own presidential candidacy ended after he lost the Florida primary in March. "He won, and he won for a reason." (Rubio noted that he "finished third, I guess, in the delegate count.")
How can he justify backing Trump after having criticized him so harshly?
"Because the one other choice is someone who I believe is corrupt," Rubio said. "I'm not supporting her, and I'm not going to abstain from voting."
Other South Florida Republicans, including former Rubio and Trump opponent Jeb Bush, have said they won't vote for either Trump or Clinton.