“I will do whatever it takes, I will campaign as long as it takes,” the Florida senator told a crowd of more than 7,000 people who encircled him on the sidelines of a high-school football field. “Donald Trump, a con artist, will never get control of this party.”

Rubio, still looking to consolidate the anti-Trump vote and to make this five-way fight a two-man race, faces the prospect of the real-estate magnate and party front-runner winning Georgia and most of the southern states that go to the polls on Tuesday — and himself emerging from “Super Tuesday” still not having won a state.

“We’re in the proportional part of the process,” Rubio told reporters. “We feel very optimistic about the amount of delegates we’re going to win. The majority of Republican voters do not want Donald Trump to be our nominee. And they are going to rally around whomever is the last one standing fighting against him.