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The Florida senator needs a victory in the winner-take-all primary slated for next Tuesday.
"Voting for John Kasich or Ted Cruz in Florida is a vote for Donald Trump," he told ABC News' George Stephanopoulos on "Good Morning America," adding that he was the only candidate who could defeat Donald Trump there.
He added that almost two in the three Republicans do not want Trump to be the nominee, despite his delegate lead. "If you have someone who’s your front-runner, and your nominee, who a significant number of your party rejects, you’re not going to win a general election.”
Rubio is trailing in the latest delegate count, needing about three-quarters of the remaining delegates to win the nomination outright, even with Florida. "It’s not going to be a traditional way to get there,” Rubio said of his winning the nomination.
"I think I’m the only candidate left in this race who can unite the Republican Party and grow the Republican Party," he said.
Rubio added that he thought he had a strong debate Thursday night, which focused on policy positions and diverged from typical brash insults seen in previous debates. "I felt good about the night we had," he said. "I think it’s an opportunity to get people who are supporting other candidates to give you a second look."
Between remote appearances on TV shows this morning, Rubio took a shot of “café Cubano” in Miami, provided by police. Officers also trucked in spare plants to decorate the camera background: Rubio’s house is two minutes down the street.