David M Jackson

USA TODAY

HOUSTON — New Jersey Gov. Chris Christie endorsed Donald Trump on Friday, the highest-profile elected official to back the New York billionaire in his pursuit of the Republican presidential nomination.

"There is no better fighter than Donald Trump," Christie said during a news conference in Fort Worth, the same day that Trump and GOP rivals Marco Rubio and Ted Cruz echoed the savage attacks on each other that marked Thursday's debate in Houston.

Christie — a potential running mate — said he believes Trump has the best chance to beat Democrat Hillary Clinton in the fall election; the New Jersey governor also defended Trump against attacks by Republicans Rubio and Cruz, saying that "desperate people do desperate things."

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Trump, who is looking to win many states during next week's Super Tuesday primaries, said he was honored by Christie's endorsement. When the New Jersey governor offered his support, Trump said he thought, "wow, that is really great.”

In explaining his decision, Christie cited a long-standing friendship with his former campaign rival and said the New York businessman can "take on the D.C. establishment," including Clinton and the Democrats. Introducing Trump before a rally in Fort Worth, Christie said the billionaire won't let Clinton get within "10 feet of the White House."

Christie himself pulled out of the presidential race earlier this month after a poor showing in the New Hampshire primary.

The stunning announcement came as Rubio and Cruz followed up on their debate attacks on Trump's business record, temperament, and proposals they declare to be unrealistic.

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During an appearance in Dallas, Rubio called Trump a "con artist" and read aloud from some of Trump's critical tweets, mocking him for misspellings ("chocker for choker").

Trump has said that Rubio sweats too much and mocked him as "Mr. Meltdown" for a poor debate performance in New Hampshire, under attack by Christie; Rubio said the New York businessman is the one who struggled during Thursday night's debate.

"He had one of those sweat mustaches," Rubio said. He also said that, during a commercial break, Trump asked for a full-length mirror: "Maybe he was trying to make sure his pants weren’t wet."

Cruz, speaking to donors in Tennessee, said he "had a lot of fun" during the debate, "I think Donald Trump had a tough night."

Trump fired back during his Fort Worth rally — especially at Rubio, who before Thursday's debate had been more reticent toward the Republican front-runner.

The billionaire described Rubio as a "choker," a "lightweight," a "nasty guy," and a "low life." He highlighted Christie's attacks on the Florida senator during the Feb. 6 debate in New Hampshire, saying "that was one of the great prosecutions I've ever seen." Trump also made a urination joke about Rubio, saying that during one event he "left a puddle in the floor."

The billionaire has described both Rubio and Cruz as a "liar" and a "basket case."

Rubio responded back during a speech in Oklahoma City, describing Trump as an "erratic guy" whose business practices have been "sticking it to the little guy" for years. Citing the billionaire's various bankruptcies and the fraud accusations surrounding the now-defunct "Trump University," Rubio told backers that "we are not going to lose the party of Reagan to a con man."

The Florida senator also downplayed Christie's endorsement, saying that "Donald probably needs a lifeline" after the Houston debate.

Cruz told reporters that the Christie endorsement could be troubling news for Rubio, but otherwise wouldn't have much significance.

Ohio Gov. John Kasich had also sought Christie's support. In a statement to CNN, Kasich spokesman Chris Schrimpf said Friday's announcement “doesn’t change anything for us. We are still the only adult in the race capable of running the country. Seems like a nightmare for Rubio though.”

It wasn't that long ago that Trump and Christie went at it back when the New Jersey governor sought the presidency. Trump mocked Christie for welcoming President Obama to New Jersey after a massive storm in 2012, saying the governor acted "like a little boy" around the president.

Christie said that Trump appeared to be running for "entertainer-in-chief."

During his surprise announcement for Trump on Friday, however, Christie denounced Rubio and Cruz as first-term senators who are inexperienced and part of the problem with government. He said voters should turn away from "amateur acts" from Washington, D.C., and look toward Trump's executive experience as a businessman.

Christie's endorsement immediately sparked speculation that he might be Trump's running mate, should he claim the Republican nomination.

Trump said Christie has "certainly got the talent" to be vice president, but "we actually haven't even talked about it."

Christie said his term as New Jersey governor expires on Jan. 19. 2018, and he has "every expectation" of fulfilling it.

Contributing: Chrissie Thompson, The Cincinnati Enquirer