Vote for home-state Gov. John Kasich in next Tuesday’s Ohio primary, not for Marco Rubio, Republicans are being urged … by Marco Rubio. It’s all part of the extraordinary tactics Donald Trump’s presidential foes are resorting to in last-ditch efforts to block the party’s front-runner.

"If you want to stop Trump in Ohio, Kasich’s the only guy who can beat him there," Rubio spokesman Alex Conant said Friday in an interview with The Associated Press.

In turn, Florida Sen. Rubio is hoping to win in his home state on Tuesday, thereby splitting the day’s two big delegate prizes and keeping them out of Trump’s hands.

While only Kasich can take on Trump in Ohio, "Marco is the only guy who can beat him in Florida," Conant said.

Polls suggest Kasich has a better chance in his state than Rubio has in Florida, but it’s important to both of them — and to Texas Sen. Ted Cruz, the other man in a four-corner fight —  to keep Trump from sweeping the two big states and taking a big step toward sewing up the Republican nomination.

Trump, for his part, showed off his latest success Friday, introducing a significant new ally at a news conference at his Palm Beach resort. Standing at Trump’s side, retired neurosurgeon Ben Carson endorsed his former GOP rival and warned that a failure to rally behind him would "fracture the party in an irreparable way."

Carson said that he and Trump had "buried the hatchet" after months of political wrangling, describing the front-runner as a "very cerebral" person.

Rubio, fighting for his political life, said it is Trump who could destroy the party given the many Republicans who vow never to support the New York real estate mogul.

"I certainly think it would fracture it," Rubio said of a Trump nomination on CBS’ "This Morning. "There is a very significant number of Republicans that will never vote for him. And you can’t win unless the party’s united."

There are signs some Ohio Republicans are already embracing the idea the Rubio camp is now pushing.

Tom Grossmann, a county commissioner and former GOP chairman in Warren County north of Cincinnati, is one Rubio supporter thinking about gong for Kasich.

"I believe Marco Rubio has the best chance of unifying the party and winning in November," he said Friday. "I don’t think he has any chance of winning in Ohio."

The fresh signs of GOP disarray followed a surprisingly civil debate Thursday night.

A restrained Trump used the latest presidential debate to send a none-too-subtle message to Republicans still wary of his insurgent candidacy: "Be smart and unify." Cruz and Rubio toned down their rhetoric, too, concluding that all-out attacks against Trump didn’t work.

"I can’t believe how civil it’s been up here," Trump declared at one point in Thursday’s face-off of the GOP’s final four.

The candidates now charge out of Miami with four days left to make their final arguments before next week’s all-important big-state presidential primaries.

Trump was heading to St. Louis and Chicago after appearing with Carson; Kasich headed for his must-win home state. Rubio made his home stand in Florida, and Cruz was shuttling from Florida to Illinois.

In all, 367 Republican delegates are at stake Tuesday in Illinois, Missouri, North Carolina, Ohio and the Northern Mariana Islands, a delegate haul that could go a long way toward determining the GOP nominee.

Democrats Hillary Clinton and Bernie Sanders, too, will be competing on Tuesday, with Clinton out to regain momentum after her startling loss to Sanders in Michigan this week.

When Thursday night’s GOP debate was over, Trump pronounced it an "elegant" discussion. He was clearly intent on projecting a less bombastic — and more presidential — image.

"We’re all in this together," he said early on, sounding more like a conciliator than a provocateur as he strives to unify the party behind his candidacy.

As for who has a realistic chance of winning the nomination, Trump simply wrote off Rubio and Kasich, saying, "There are two of us that can, and there are two of us that cannot, OK?"

Rubio said Friday, "As far as Florida’s concerned, we feel good, we’re making progress, we have real momentum here now."

(Copyright (c) 2016 Sunbeam Television. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)

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