Their friendship started after an introduction by means of Donald J. Trump’s sister. It ended almost 20 years later, when Mr. Trump refused to concede the 2020 election to Joseph R. Biden Jr.

In between, Chris Christie, the previous governor of New Jersey, and Mr. Trump had a relationship that could possibly be genuinely heat, with chats about politics and present occasions, and at different occasions transactional.

Mr. Christie gave Mr. Trump a lift by endorsing his 2016 candidacy after ending his personal bid for the Republican nomination, after which coached him for debates and led his preliminary presidential transition staff. In return, Mr. Trump handed him over for the roles of vp and legal professional common.

Mr. Trump ultimately turned again to Mr. Christie for different recommendation throughout his time period. But by the halfway level of the presidency, Mr. Christie appeared content material to be on the surface.

Their final change was in August 2021, in accordance with an individual briefed on the matter, when the previous president had an aide ship Mr. Christie a testy message.

Now, they’ve entered a brand new chapter: open hostility. Mr. Christie announced his second presidential campaign on Tuesday in New Hampshire, aiming to cease Mr. Trump from a second time period within the White House.

“I think he’s a coward and I think he’s a puppet of Putin,” Mr. Christie, talking lately to the conservative radio host Hugh Hewitt, mentioned of the person he as soon as supported.

Here’s a glance again at how their relationship grew, thrived after which wilted.

Casual Acquaintances, Then Presidential Rivals

Mr. Christie was a United States legal professional in New Jersey, the place Mr. Trump nonetheless had casinos, when the 2 males first dined collectively.

That May 2002 introduction over dinner got here by means of an middleman, Maryanne Trump Barry, Mr. Trump’s older sister, who was a federal decide within the state on the time and described Mr. Trump to Mr. Christie as “my little brother.” In Mr. Christie’s 2019 memoir, “Let Me Finish,” he wrote about his first impressions of Mr. Trump, who in two years would start his run because the star of the fact TV present “The Apprentice.”

“Donald was opinionated,” Mr. Christie wrote. “He was bombastic. He was entertaining. He talked about his business with infectious enthusiasm and considerable detail. I came away with the impression that public Donald and the private Donald were pretty much one and the same.”

It was quickly clear that Mr. Christie may find yourself as a candidate for governor sometime. He received the workplace in his first try, in 2009, two years earlier than Mr. Trump thought-about working for the White House in opposition to President Barack Obama.

Both males knew one another in the way in which that outstanding individuals within the New York media market are likely to: casually, with paths that periodically crossed.

In 2015, each Mr. Christie and Mr. Trump ended up declaring presidential candidacies.

Mr. Christie, by then hobbled by the “Bridgegate” political retribution scandal, had nonetheless usual a nationwide political model as a straight-talking candidate.

By distinction, some seen Mr. Trump as a sideshow who would ultimately fade, at the same time as he was main within the polls. At the time, Mr. Trump informed Mr. Christie privately that he didn’t anticipate his marketing campaign to final past October 2015.

Their relationship started to be examined. Two months after Mr. Trump’s entrance into the race, Mr. Christie informed Fox News that the New York businessman didn’t have the “temperament” or expertise to be president. Mr. Trump taunted Mr. Christie for being absent from New Jersey, the place he was nonetheless governor.

Ultimately, Mr. Trump overshadowed his newfound rival — and all different rivals — with an infinite stream of inflammatory pronouncements, together with a proposal to ban Muslims from getting into the nation.

Mr. Trump saved his most hostile barbs for candidates apart from Mr. Christie. In flip, the governor skilled his most aggressive fireplace on Senator Marco Rubio of Florida throughout a debate in New Hampshire shortly earlier than the state’s major, mocking him for a “memorized 25-second speech.”

But after staking his candidacy on New Hampshire, Mr. Christie completed a dismal sixth and dropped out of the race.

A Key Ally, Up to a Point

When Mr. Trump received the South Carolina major, Mr. Christie informed allies the writing was on the wall — it was clear Mr. Trump was on observe to grow to be the nominee.

“I am proud to be here to endorse Donald Trump for president of the United States,” Mr. Christie mentioned at an endorsement event in Florida in February 2016, as astonished reporters watched him reward Mr. Trump’s candidacy. After Senator Jeff Sessions of Alabama, Mr. Christie was one of many first outstanding Republicans to endorse Mr. Trump at a time when the occasion’s management was nonetheless attempting to cease his ascent.

Soon, Mr. Christie was a key adviser to Mr. Trump. He was additionally for a time thought-about as a possible working mate, however a few of Mr. Trump’s advisers, together with members of his household, argued in opposition to it. (Mr. Christie had additionally prosecuted the daddy of Mr. Trump’s son-in-law Jared Kushner years earlier, and Mr. Kushner was against the choice of Mr. Christie.)

Mr. Trump in the end selected Mike Pence, then the governor of Indiana, who had been launched to Mr. Trump by means of Mr. Christie.

Mr. Trump tried to maintain Mr. Christie on the hook, the previous governor wrote in his memoir, insisting in a cellphone name to Mr. Christie that he hadn’t selected his working mate but, at the same time as he made plans to fly Mr. Pence to New York for a news convention.

Mr. Christie led Mr. Trump’s preparations for the general-election debates in opposition to Hillary Clinton, the Democratic nominee. But after the October 2016 launch of a recording by which Mr. Trump described grabbing ladies by their genitals, Mr. Trump privately griped that Mr. Christie had no more vocally backed him.

Mr. Christie additionally served as the top of his transition staff, a job from which he was dismissed shortly after Election Day by Mr. Kushner; Stephen Okay. Bannon, the chief strategist for Mr. Trump; and Reince Priebus, who would grow to be Mr. Trump’s first White House chief of workers.

Behind the Scenes, Distancing

Mr. Trump requested Mr. Christie to guide a activity pressure on opioids, a problem Mr. Christie had been involved about as governor. Mr. Christie was additionally mentioned to be a private favourite of Mr. Trump’s spouse, Melania.

But Mr. Trump determined in opposition to giving him the job of legal professional common, which went to Mr. Sessions. Instead, Mr. Christie has mentioned, the president supplied him numerous roles at totally different factors, together with labor secretary and secretary of the Homeland Security Department.

Mr. Trump additionally took a suggestion from Mr. Christie as to who may substitute the fired F.B.I. director, James A. Comey. It was Mr. Christie’s lawyer through the Bridgegate scandal, Christopher A. Wray, who was appointed and stays atop the company. Mr. Trump quickly began complaining that Mr. Wray was not doing what he needed on the company, and blamed Mr. Christie for a nomination that Mr. Trump had put ahead.

Mr. Christie took himself out of consideration to succeed John F. Kelly as Mr. Trump’s chief of workers on the finish of 2018 after Mr. Trump had supplied the job to Mr. Christie. By then, it had grow to be clear that Mr. Trump was biking by means of workers members and firing them at a speedy clip.

In February 2020, Mr. Trump pardoned a former software program chief govt whose clemency Mr. Christie had lobbied for.

That yr, Mr. Christie wrote Mr. Trump a prolonged memo instructing him how one can deal with the coronavirus pandemic. It was ignored.

Mr. Trump introduced Mr. Christie in for debate preparations as soon as once more, and a few of his aides faulted Mr. Christie when Mr. Trump’s preliminary debate in opposition to Mr. Biden was disastrous. (Mr. Trump appeared bodily unwell on the debate and should have already been affected by the coronavirus; the news of his Covid diagnosis came days later.)

When each Mr. Trump and Mr. Christie have been hospitalized with severe bouts of Covid shortly after that debate, Mr. Trump known as his debate coach on the hospital. “Are you going to say you got it from me?” Mr. Trump requested Mr. Christie, the previous governor later recounted in his second ebook, “Republican Rescue.” They each recovered, however Mr. Christie made clear he thought he ought to have worn a masks on the prep classes, angering Mr. Trump.

Breakup

Hours after Election Day ended, when Mr. Trump delivered a speech claiming widespread fraud, Mr. Christie, by then a contributor for ABC News, mentioned on air that Mr. Trump wanted to supply proof.

In an interview with The New York Times in November 2022, Mr. Christie mentioned he had final spoken with Mr. Trump in December 2020, after the president noticed him deride Mr. Trump’s authorized staff on tv. Mr. Christie informed him he ought to concede the election to Mr. Biden and host the president-elect within the White House.

“He told me he would never, ever, ever, ever do that,” Mr. Christie mentioned. “And that was the last time we spoke.”

In 2021, Mr. Trump described Mr. Christie as an “opportunist” to a reporter. Four months later, he had an aide ship Mr. Christie a printout of a tweet by Mr. Christie associated to the pardon that he had searched for the previous software program govt. “Chris,” he wrote, in accordance with the individual briefed on it, “How quickly people (some) forget – Best Wishes,” together with his signature.

Mr. Christie responded cordially, wishing Mr. Trump effectively.

Shane Goldmacher contributed reporting.