Christie, In About-face, Endorses Former GOP Rival Trump

New Jersey Gov. Chris Christie, right, introduced Republican presidential candidate Donald J. Trump after endorsing him before a rally at the Fort Worth Convention Center in Fort Worth,Texas, Friday, Feb. 26, 2016. Christie backed Trump in the Republican race for president Friday, a powerhouse endorsement as the billionaire tries to beat back assaults on his character from a newly aggressive rival, Marco Rubio. (Tom Fox/The Dallas Morning News) MANDATORY CREDIT; MAGS OUT; TV OUT; INTERNET USE BY AP MEMBERS ONLY; NO SALES

New Jersey Gov. Chris Christie has a reputation for vengeance.

And he delivered it with gusto on Friday as he shocked many in the political world by endorsing GOP front-runner Donald Trump for the Republican presidential nomination.

The surprise endorsement, the first for Trump from a sitting governor and by far his most prominent, comes as Trump rival Marco Rubio appeared on the cusp of a breakthrough following a break-out debate performance. And it marks the second time that Christie has knee-capped the Florida senator, just as he appeared to be on the rise.

At the news conference in Fort Worth, Texas, Christie described Trump — a man he had previously panned as ill-suited for the White House — as the best Republican candidate to lead the country and beat Democrat Hillary Clinton.

"I've gotten to know all the people on that stage and there is none who is better prepared to provide America with the strong leadership that it needs both at home and around the world than Donald Trump," Christie said. Reporters covering the event were visibly stunned when the governor, who dropped his own bid for the presidency earlier this month following a disappointing finish in New Hampshire, walked into the room.

The endorsement comes at a particularly opportune time for the real estate mogul, who on Thursday night faced a barrage of new attacks from Rubio during the final debate ahead of next week's Super Tuesday contests, where large numbers of delegates are at stake. During the debate, Rubio hit at Trump's business record, history of hiring foreign workers and his vague policy positions. The broadsides clearly irritated Trump and threatened to provide Rubio with a jolt of new momentum as he seeks to turn the contest into a two-man race.

Rubio appeared to be flying high on Friday morning, delivering new Trump attack lines, including mocking his spelling on Twitter, with newfound glee.

But then, in charged Christie to steal the news cycle and momentum.

"I think this changes the narrative in a dramatic way," said Fred Malek, a major Republican fundraiser, of Christie's decision.

The timing immediately following the debate appeared to be a coincidence. A former Christie campaign official said the governor made his decision to endorse Trump on Thursday following a meeting in Manhattan attended by the two men and their wives. Christie was already on a plane heading to Texas as the debate was airing, according to the former official, who was not authorized to speak publically on Christie's behalf and spoke on the condition of anonymity.

But it was nonetheless the second time Christie has managed to tear down Rubio just as he was on the rise. During the last GOP debate before the New Hampshire primary, as Rubio appeared on the cusp of a breakthrough, Christie set a verbal trap that left Rubio repeating the same practiced line over and over again.

It was a high moment for Christie's campaign - and especially personal. Christie has grown deeply resentful of Rubio. Some of that anger stemmed from a super PAC supporting the Florida senator that was responsible for much of the negative advertising that Christie's campaign and his allies have blamed for his loss in the race. Throughout his campaign, Christie bashed the baby-faced senator as inexperienced, drawing parallels with another first-term-senator-turned-president, Barack Obama, and blasted Rubio for his frequent missed votes and Washington insider status.

Ironically, Christie's tactic was the same one used so effectively by Rubio against Trump on Thursday night, as he forced the billionaire to repeat the same talking points to describe a health care plan thin on detail. "I just watched you repeat yourself five times five seconds ago," Rubio said.

With his endorsement, Christie is now back in the game, and his role now appears to be that of attack dog. Christie appeared to embrace the role within minutes of announcing his endorsement, painting Rubio as a desperate man on the cusp of losing the race.

And Trump appeared to relish the attacks, repeatedly mentioning Christie's take-down of Rubio during that pre-New Hampshire debate.

"I gotta tell you, Chris was so - wow, what he did. That was one of the great prosecutions I've ever seen," Trump raved at a post-endorsement rally.

"I watched Chris take a man apart," he added. "And honestly, I thought he was going to die, Rubio. He was so scared like a little frightened puppy."

This story has been edited to correct reference to Rubio as 'senator,' instead of governor.

By JILL COLVIN - Feb. 27, 2016 4:54 AM EST