FORT MYERS, Fla. — Anxious Republican officials are coming to terms with the idea that their second least favorite GOP presidential candidate — polarizing Texas conservative Ted Cruz — may be the party’s best last chance to stop Donald Trump.

Possible Cruz supporters include reluctant Senate colleagues and former presidential rivals with strong ties to major donors, who have long feared Cruz’s purist ideology but dread the prospect of a Trump nomination even more. The first-term Texas senator on Wednesday announced the backing of one former primary opponent, Carly Fiorina, and is seeking the backing of another, Jeb Bush, on Thursday.

“It’s an outsider year, and the most logical person to take on Trump based on past performance is Ted Cruz,” said another former presidential opponent, South Carolina Sen. Lindsey Graham. Earlier in the year, Graham likened the choice between Cruz and Trump to “being shot or poisoned.”

“He’s not my preference,” Graham said of Cruz. “But we are where we are. And if Trump wins Florida and Ohio, I don’t know if we can stop him.”

Indeed, next Tuesday’s winner-take-all contests in Florida and Ohio have injected a sense of urgency into the GOP’s anti-Trump movement.

The billionaire businessman is calling on mainstream Republicans to unify behind his candidacy ahead of next week’s primaries, which could give him an insurmountable delegate lead.

“If I win those two, I think it’s over,” Trump told CNN’s “Anderson Cooper’s 360.”

“Instead of fighting it, they should embrace it,” he added on Fox News Channel.

Bush planned to confer with all the candidates — save Trump — ahead of Thursday’s GOP debate. He met privately with Florida Sen. Marco Rubio on Wednesday, and planned to meet with Cruz and Ohio Gov. John Kasich on Thursday.

Bush and Trump engaged in heated confrontations throughout Bush’s campaign, repeatedly referring to each other as “loser.”

The GOP establishment’s overwhelming favorite, Florida Sen. Marco Rubio, picked up where Bush left off, but struggled badly in Tuesday’s round of primary contests, failing to pick up a single delegate. Trump won three of the contests and Cruz won one.

Now, in the midst of a weeklong march through Florida to save his candidacy, Rubio concedes that he went too far in insulting Trump.