Marco Rubio continues to slam Donald Trump

Marco Rubio spoke in Oklahoma City on Friday.J Pat Carter/Getty Images

WASHINGTON — The Republican establishment has begun to find its voice with the resurgence of Florida Senator Marco Rubio, who continued to pummel Donald Trump on Friday and even tried to turn the tables on Trump by joking that the New York mogul wet his pants the previous night on the debate stage.

But even as Rubio latched onto Trump’s own schoolyard bullying tactics in an effort to counter Trump’s seemingly unfettered romp through the Republican primary field, Trump scored a new coup with a surprising endorsement from New Jersey Governor Chris Christie.

Christie on Friday said Trump has outsider credentials to bring change to Washington. ‘‘We don’t need any more of these Washington, D.C., acts,’’ Christie said, citing Rubio’s frequent absences from Senate votes while he has been campaigning.

Christie had dropped out of the GOP presidential contest after a weak showing in New Hampshire, but not before memorably eviscerating Rubio in a Granite State debate for robotically reciting his lines.

Also Friday, Maine Governor Paul LePage offered his endorsement of Trump while on ‘The Howie Carr Show.’’

The famously pugnacious governor said Trump owes him for paving the way when it comes to being outspoken. ‘‘I was Donald Trump before Donald Trump became popular, so I think I should support him since we are one of the same cloth,’’ LePage said.

The battle for the Republican nomination — largely between Rubio and Trump — intensified with just four days to go until Super Tuesday, when Trump, if he maintains his current lead in polls, could rack up enough victories to make him difficult, if not impossible, to stop.

Rubio on Thursday night had the breakout debate performance against Trump that many in the Republican Party have wanted to see for months. He was forceful, relentless, and showed no hesitancy at interrupting the brash businessman, who appeared knocked off kilter several times.

Rubio on Friday continued to ramp up his attacks on Trump, calling him a “con artist” and vowing to pressure the business mogul into releasing his tax returns.

“He’s a con artist. It’s a fraud,” Rubio said on ABC’s “Good Morning America.” “We’re going to expose him.”

At a campaign rally in Dallas Friday, Rubio read Trump’s tweets from the stage and recalled a backstage moment from Thursday’s debate: He said Trump asked for a full-length mirror during a break. “Maybe to make sure his pants weren’t wet,” Rubio quipped, adding that backstage, Trump was applying makeup to his upper lip “because he had one of those sweat mustaches.”

Trump responded by calling Rubio “a mess” and a “little frightened puppy.” He described Rubio “piling on makeup” with a “trowel” backstage Thursday.

Many in the party establishment who want to stop Trump worried: Has Rubio’s newly aggressive strategy come too late? Trump has leads in nearly all of the 11 states that vote in the Super Tuesday primary, and he has won three states in a row — New Hampshire, South Carolina, and Nevada.

The prospect of a Trump nomination is becoming increasingly real.

“I’m very fearful — one, of him being president, and two, of our ability to hold on to the Senate,” Senator Jeff Flake of Arizona said in an interview on his way to a Republican Senate lunch this week. “It’s become more worrisome all the time.”

Flake, who threw his support behind Rubio on Monday, said he does not believe Trump will appeal to the broader electorate.

“I’m afraid he’s got a lower ceiling than we’re going to need to win the election,” Flake said, referring to the vote Trump would attract in a general election. “Some of the statements he’s made about Muslims and certain ethnic groups here and disabled people and everything else just makes it very tough to grow the party.”

Senator Lindsey Graham, the South Carolina Republican who dropped out of the presidential race in December after never gaining traction, told the Globe that Republicans would have to rebuild the party if Trump becomes the nominee. Mitt Romney lost in 2012 in part because the party did not draw enough young women and Hispanic voters.

Trump’s candidacy, Graham said, would exacerbate the problem. “We’ll get slaughtered in November. We’ll lose Hispanics in large numbers. Our problems with young women will get worse,” Graham said. “We’re in a world of hurt.”

Rubio has 13 endorsements from fellow senators, some of whom fretted about maintaining Republican control of the Senate if Trump were the nominee.

“If you were to ask our endangered 2016 senators, they would probably tell you that they would rather not have him as the standard bearer,” said Senator James Inhofe, an Oklahoma Republican who endorsed Rubio last month.

As for how their Democratic colleagues are feeling about Trump?

“Giddy!” said Senator Chris Murphy, a Connecticut Democrat. “There’s no way that he could survive a general election environment.”

Indeed, Rubio’s attacks in the Thursday debate also served as a not-so-subtle warning about Trump’s electability, with a list of negative issues that a Democratic nominee could use against him in the general election. Rubio dredged up Trump’s record of illegally hiring Polish immigrants to prepare the site for Trump Tower in New York; he mentioned news coverage about Trump hiring legal immigrants to work at a resort in Florida; he slammed Trump for lawsuits against Trump University that alleged fraud.

He also called on Trump to release his tax returns, alluding to an issue that former Massachusetts governor Mitt Romney this week said could be a “bombshell’’ lying in wait. Trump responded during the debate that he is being audited by the IRS and, without providing a specific timeline, said he would release his returns when the audits are complete.

Rubio’s campaign plans to keep pushing the tax issue in the final days before Super Tuesday. “It is a bit concerning that the guy who wants to be commander in chief says, ‘Look I can’t release my tax returns because I’m being audited,’ ” said Terry Sullivan, Rubio’s campaign manager. “Like, what the hell is that? ‘P.S. I’m being sued at the same time for defrauding people.’ ”

David Axelrod, the chief political strategist during Barack Obama’s two successful national elections, said the debate was “a taste of what it would be like if Trump were treated with the same scrutiny as others. And there’s a lot of material to work with.”

“So much of his campaign rests on his aura as an uber businessman when what he mostly has been is a masterful self-promoter,” Axelrod said.

Rubio’s campaign is increasingly concerned that with Ohio Governor John Kasich and Senator Ted Cruz still in the race, Rubio will have a tougher challenge in attempting to consolidate the party against Trump.

Kasich shows no signs of backing down and recently captured several new big-money donors who can keep his campaign alive. His campaign believes he can win the race by being the responsible governor who stays above the fray.

“Kasich was the only guy up there with substance, with ideas, acting like an adult, acting presidential,” said John E. Sununu, the New Hampshire Republican who has endorsed Kasich. “The others on the stage were throwing spitballs. It was embarrassing to watch.”’