Republican presidential candidates fought over immigration reform, health care and peace in the Middle East during the CNN/Telemundo debate in Houston on Feb. 25. (Sarah Parnass/The Washington Post)

Republican presidential candidates fought over immigration reform, health care and peace in the Middle East during the CNN/Telemundo debate in Houston on Feb. 25. (Sarah Parnass/The Washington Post)

In the 10th Republican debate, Donald Trump was finally treated like a front-runner: He was relentlessly attacked, sometimes on the same personal terms that Trump has hurled at others.

Sen. Marco Rubio (Fla.) sought to turn Trump’s biggest strength — his business record — into a weakness, casting him as a shady actor who peddled a “fake” university and used undocumented immigrants on a major project.

[Live updates from the debate]

“If he hadn’t inherited $200 million, you know where Donald Trump would be? Selling watches in Manhattan,” Rubio said at one point. He began and ended the debate with veiled jabs at the way the reality TV star has changed this race: “The silliness. This looniness!” Rubio said in his closing statement.

Sen. Ted Cruz (Tex.) criticized Trump for his changes of position on political issues, and at one point even seemed to intimate he needed medication to stay calm.

“Donald, you can get back on your meds now,” Cruz said at one point. “You can relax.”

Trump responded with equally personal attacks on the two senators, deriding Rubio as someone who was easily rattled and Cruz as a friendless outcast in the Senate, who used dirty tactics on the campaign trail.

“This guy’s a choke artist,” he said, meaning Rubio. “And this guy’s a liar,” he said, meaning Cruz.

This debate, held in Houston and broadcast on CNN, was the last chance for Rubio and Cruz to undermine Trump before the vital Super Tuesday primaries next week. And in battling Trump, the two were battling each other: Each wanted to show GOP donors that he was the strongest opponent for Trump and cause a consolidation that would force the other man out.

[Republicans ask: Can Donald Trump be stopped?]

At multiple points the debate turned into a shouting match, with Trump, Cruz and Rubio speaking over one another. The other candidates on the stage, retired neurosurgeon Ben Carson and Ohio Gov. John Kasich, seemed mostly happy to be bystanders while Rubio, Cruz and Trump fired upon each other.

Kasich repeatedly condemned the arguments onstage and used his opening statement to make a nonpolitical remark, urging children to follow their dreams: “America is great, and you can do it,” Kasich said.

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Carson, as usual, was a mild presence but showed a gift for vivid metaphor. Asked how he would evaluate a potential Supreme Court appointee’s record, Carson responded: “The fruit salad of their life is what I would look at.”

Later, feeling left out of the debate, he said, “Can somebody attack me, please?”

Trump sometimes violated Republican taboos. He criticized President George W. Bush, praised Planned Parenthood, and offered a kind of muddled praise for government-provided health insurance.

He offered a backhanded appreciation of two Arab dictators who had been fierce enemies of past Republican administrations, saying that Iraqi dictator Saddam Hussein and Libyan strongman Moammar Gaddafi should have been left in power.

“If we had Saddam Hussein and we had Gaddafi in charge,” both countries would be more stable and terrorists would not have seized control of parts of those countries, Trump said.

“They were bad, they were really bad, [but] we would have been better off if the politicians had taken the day off and not gone into war,” he said.

That was a remarkable statement from a GOP front-runner: Both regimes had been the subject of U.S. military action ordered by Republican presidents. George W. Bush ordered the 2003 invasion of Iraq in which Saddam Hussein was executed, and Ronald Reagan ordered airstrikes on Libya in 1986 after Gaddafi’s regime was tied to the bombing of a Berlin disco.

[Two former Mexican presidents take aim at Trump and his ‘stupid wall’ ]

[ Shouts of ‘liar’ are taking their toll on Ted Cruz’s campaign]

Trump’s tax returns audited

Trump also attacked former Republican presidential nominee Mitt Romney, calling him “a fool” for delaying the release of his tax returns in the 2012 election. Trump said he would delay releasing his own tax returns, blaming the timing on an IRS audit.

“Mitt Romney looked like a fool when he delayed and delayed and delayed. . . . As far as my return, I want to file it. Except,” Trump said, “I can’t do it until the audit is finished.”

This week, Romney — who received Trump’s endorsement in 2012 — predicted that there would be a “bombshell” in Trump’s tax returns.

When pressed by debate moderator Hugh Hewitt, Trump responded by referring to the ratings of Hewitt’s conservative radio show.

“First of all, very few people listen to your radio show,” Trump said. “I want to release my tax returns. But I can’t release them while I’m under audit.”

Cruz jabbed at Trump over lawsuits alleging that “Trump University” defrauded its students.

“I want you to think about . . . having the Republican nominee on the stand in court, being cross-examined about whether he committed fraud,” Cruz said.

Trump responded, as he has before, by pointing to poll numbers. He noted that Cruz was trailing him in many states — and that even polls in Texas showed that Cruz might be in trouble.

“You’re not beating Hillary,” Cruz said, meaning the Democratic front-runner, Hillary Clinton.

“If I can’t beat her, you’re really going to get killed,” Trump said to Cruz. Then, in mock encouragement, he said, “Keep fighting, keep fighting, keep swinging for the fences.”

Rubio and Cruz often tag-teamed in attacking Trump, calling him a poor businessman, a shaky conservative, and — turning around an attack used against Rubio — prone to repeating himself.

“So that’s the only part of the plan? Just the lines?” Rubio said, hammering Trump for repeatedly saying his health-care plan was to “get rid of the lines” that block insurers from selling insurance across state lines. “Now he’s repeating himself.” The audience laughed, because Rubio had been mocked for robotically saying the same talking point in a past debate under pressure from New Jersey Gov. Chris Christie, now out of the race.

Cruz took up the attack, although with a different thesis: Where Rubio had blasted Trump for not having a health-care plan, Cruz attacked him for having a health-care plan that was too complicated and government-centric. He said that Trump’s “socialized medicine” could lead to rationing that would deny elderly people hip and knee replacements.

“Does the government pay for health care? Yes or no? Answer the question!” Cruz said.

“I do not want socialized medicine,” Trump responded, but did not detail his health-care plans beyond a desire not to see people die on the sidewalk, a nod to some sort of medical safety net.

Super Tuesday

Thursday night’s debate comes less than a week before the critical Super Tuesday elections, when Republicans in 11 states will go to the polls, deciding the allocation of 595 convention delegates.

Trump, who in the Nevada caucuses claimed more votes than Cruz and Rubio combined, said that he was reshaping the Republican Party by drawing in a wider group of people.

“We are building a new Republican Party. A lot of new people are coming in,” Trump said, responding to a question about how he would attract Hispanic voters after calling for a mass deportation of undocumented immigrants. “I will do really well with Hispanics. I will do better than anybody on this stage . . . I’m telling you also, I’m bringing people, Democrats over, independents over, and we’re building a much bigger, much stronger Republican Party.”

Rubio and Cruz challenged Trump’s shifting on issues important to conservatives.

“We’re always looking for converts into the conservative movement,” Rubio said, meaning that Trump was a recent convert. He was responding to a question about the successor that a President Trump might appoint in place of the late Supreme Court Justice Antonin Scalia, a conservative icon: “I have a doubt about whether Donald Trump, if he becomes president, will replace Justice Scalia with someone like Justice Scalia.”

Trump seemed willing to break with conservative orthodoxy, praising Planned Parenthood, an institution reviled by many on the right because of its involvement in abortion: “Millions and millions of women, cervical cancer, breast cancer, are helped by Planned Parenthood,” Trump said. “I would defund it because I’m pro-life, but millions of women are helped by Planned Parenthood.”

Rubio gets aggressive

From the opening moments, Rubio launched a volley of attacks at Trump.

He focused one attack on one of the front-runner’s strengths: his business record. Rubio criticized the management of “Trump University,” his bankruptcies at his companies, and his use of undocumented immigrants to work on one of his properties in New York.

Trump responded by saying that Rubio had exaggerated his inheritance from his father and had never run a business. He referred to a case in which Rubio sold a house to a lobbyist at a significant profit: “He sells it to a lobbyist, who’s probably here,” Trump said.

In the first hour of the debate, Rubio was strikingly more aggressive than he had been, and Trump — who had benefitted as other candidates attacked one another — was the subject of a number of attacks. Rubio and Cruz teamed up to attack Trump for switching his position on immigration — and for hiring illegal immigrants — taking the fight to the Republican front-runner at a moment when he is close to running away with the race.

“You’re the only person on this stage that’s ever been fined for hiring people to work on your projects illegally,” Rubio said, referring to a decades-old legal judgment against Trump for hiring undocumented Polish workers at one of his projects in New York. At the time, Trump said that he did not know the workers were undocumented.

“I’m the only one on this stage that’s hired people,” Trump said in a rebuke to Rubio, who has spent nearly all of his life in politics.

“People can look it up,” Rubio said, pressing on. “I’m sure people are Googling it right now.” As the two talked over each other (“Wrong. Wrong.” “That happened!”), Trump used the same tactic he had used on former Florida governor Jeb Bush, now out of the race: “Let me talk.”

Cruz hits back

Cruz picked up the attack, saying that he had battled a 2013 effort to pass immigration restructuring and give undocumented immigrants a legal pathway to citizenship.

“Where was Donald? He was firing Dennis Rodman on ‘Celebrity Apprentice,’ ” Cruz said, mocking Trump’s long career in reality television. He said Trump had donated to many of the bill’s sponsors: “When you’re funding open-border politicians, you shouldn’t be surprised when they fight for open borders.”

Trump had a comeback ready, based on Cruz’s unpopularity in the Senate: “You get along with nobody,” Trump said. “You don’t have one Republican senator backing you. Not one.”

Cruz had a comeback for that, too, although it lacked some of the zing of Trump’s: “Donald, if you want to be liked in Washington, that’s not a good attribute for a president.”

Rubio began the debate with a veiled attack on Trump, saying that he hoped the Republican Party would not lose the hopeful identity that came from Reagan and George H.W. Bush.

“They also appealed to our hopes and our dreams. Now we have to decide if we’re still going to be that kind of party,” Rubio said. “Or if we’re going to be a party that preys on people’s anger and fear.”

Rubio had signaled before the debate that he intended to be more harshly critical of Trump, who has benefitted as Rubio, Cruz and others battled in his shadow. That opening statement was a sign that he might — although he didn’t mention Trump by name. Trump has called for mass deportation of millions of undocumented immigrants and for barring Muslims from entering the United States.

Rubio attacked Trump for changing his positions on immigration — and for hiring foreigners to work at his properties in Florida.

“Donald, you’ve hired a significant number of people from other countries to take jobs that Americans might have filled,” Rubio said, noting that his mother — an immigrant from Cuba — worked as a maid at a hotel, and that people such as she would have been excluded from Trump’s properties.