MANCHESTER, N.H. — Was it all a mirage, this notion of a Republican Party open to abandoning Donald Trump in 2024? For all the vulnerabilities attributed to him at this time last year, and there were some, they quickly melted away. The Republican nomination was never to be a fair fight.

The last round has not yet played out. There will be a primary election here on Tuesday and maybe another in South Carolina in late February, and who knows what after that. But the end of any real competition could come very soon. The decision on Sunday by Florida Gov. Ron DeSantis to quit the race and endorse the former president was the biggest acknowledgment that the script has been written.

For Trump, DeSantis’s withdrawal and endorsement was one more trophy to put on the shelf, the latest of his challengers to humbly fall in line. For the Republican Party, however, it is a reminder that it probably will enter the fall campaign with a deeply flawed standard-bearer, one who sharply divides the electorate, motivates Democrats as few other Republicans do and could yet be a felon by Election Day.

Trump’s team sees President Biden as even more flawed. But Republicans are deciding not to turn the page from the Trump era and will rise or fall on that basis. The coming general election between these two politicians, which a majority of Americans say they wish would not happen, will not be uplifting but will be enormously consequential, given what Trump has said about a second term of retribution.

Nikki Haley, Trump’s last remaining challenger, will soldier on through Tuesday’s contest. She was on the campaign trail in New Hampshire on Sunday appealing as directly as she could to independent voters to give her a boost. They are her one real hope to cut into Trump’s lead here and convince Republicans elsewhere that he is too vulnerable to pick as the nominee.

Most polls of New Hampshire voters, however, look bad for her here. If she loses by what some of these polls show — a double-digit defeat — she will have to decide whether to continue to her home state of South Carolina, where she could face the possibility of being rejected and possibly humiliated by people who put her in the governor’s mansion and therefore know her best.

For any politician, that choice is excruciating, one that weighs pride and determination against future viability in a post-Trump Republican Party. DeSantis decided not to face his constituents in Florida’s March 19 primary. He scampered out long before, hoping that an early exit, before further embarrassments, and a retreat to the friendlier terrain of Tallahassee, will prove to be restorative, personally and politically. He could live to fight another day.

The Republican contest offered the possibility at least of competition. But that was because DeSantis had started on an upswing, thanks to his big reelection victory in 2022 and Trump’s stumbles in those same midterm elections.

But almost every twist and turn in this Republican campaign has accrued to Trump’s benefit. Four indictments and 91 felony counts? Wouldn’t that make Republicans question whether Trump should be their nominee? The answer was resounding. The indictments consolidated his support rather than fracturing it. That was the biggest of the game changers.

Another was the woeful performance by DeSantis. Ill-prepared to make the jump from state to national politics, he misjudged things repeatedly. He was treated as a candidate before he was ready to announce, a miscalculation that led to unforced errors. He started as a poor performer and never was able to overcome the early mistakes. He said he would do for the nation what he had done for Florida. That turned out to have minimal appeal.

Over months of campaigning, DeSantis improved as a candidate, but first impressions dogged him to the end. So, too, did the colossal disarray in his campaign and a super PAC called Never Back Down that became a snake pit of warring factions. On Sunday, the candidate of Never Back Down did back down, receding quietly to the sidelines.

Then there was the supposed battle for second place and the opportunity to square up against Trump. The way that played out couldn’t have made Trump and his team happier. DeSantis and Haley spent millions attacking each other, each making the other as unacceptable as possible to a broad share of the Republican base.

When they were on the debate stages, which Trump strategically avoided, they fired at each other in a cacophony of insults and accusations, each trying to drown out the other. Commentators tried to discern who won each of those encounters, but the real story was that Trump was the winner. The squabbling by his rivals diminished them. By refusing to debate, he was able to stand above the fray, no doubt smiling at what it saw — if he watched at all.

More helpful to Trump was that neither DeSantis nor Haley nor their super PACs spent any real money trying to stop or even slow him. Oh, they toyed with attacking him in some of their campaign appearances, but their hearts have never seemed in it.

DeSantis tried to say that he would deliver results as president that Trump did not and that a Trump-Biden race would give the Democrats an opportunity to remind the country of what happened on Jan. 6, 2021, when Trump loyalists attacked the Capitol, rather than a focus on the future.

Haley continues to say that chaos follows Trump and that the country can’t afford more — and this weekend, after Trump mixed her up with former House speaker Nancy Pelosi, she questioned his mental acuity.

Trump, meanwhile, reveled in nasty and sometimes personal attacks against both of them. The Trump team, seeing DeSantis as potentially the strongest challenger, set out early to demolish his candidacy. When they were satisfied that he had no path to the nomination, they turned on Haley, pounding her with television ads.

Over this weekend, Trump brought a cavalcade of elected officials from South Carolina who are backing him, including Sen. Tim Scott and Gov. Henry McMaster, to New Hampshire to try to blunt whatever momentum Haley has — and to show her what could come at her if she does continue on to compete in her home state.

Haley now has what she has wanted. She is the last candidate standing against Trump, something that the anti-Trump faction within the Republican Party long has wanted.

Trump benefited in 2016 from a fractured field of candidates who declined to quit when it was clear they had no chance. Now the field has winnowed even earlier than might have been expected. On Tuesday, Haley will either prove or not that there is still significant hunger among enough Republican voters to select a nominee other than the former president. Then it could be decision time for her, as it was for DeSantis, Chris Christie, Tim Scott, Mike Pence, Asa Hutchinson, Doug Burgum and Vivek Ramaswamy.

For Democrats, a swift end to the Republican contest is what they claim they want, forcing voters to recognize that their choice in November will be between the president and the former president, a contrast they argue plays to Biden’s advantage.

Maybe that will be the case, though there is nervousness in Biden’s party given his weak political standing right now. There will be nervousness among Republicans, as well, for they are showing they prefer to cast their lot with the man who both lost the last general election and faces a spring and summer sitting in a courtroom.