Throughout the Republican Party, from New Hampshire to Florida to California, many leaders, operatives, donors and activists arrived this week at the conclusion they had been hoping to thwart or at least delay: Donald Trump will be their presidential nominee.

An aura of inevitability is now forming around the controversial mogul. Trump smothered his opponents in six straight primaries in the Northeast and vacuumed up more delegates than even the most generous predictions foresaw. He is gaining high-profile ­endorsements by the day — a legendary Indiana basketball coach Wednesday, two House committee chairmen Thursday. And his ­rivals, Sen. Ted Cruz of Texas and Ohio Gov. John Kasich, are making the kind of rushed tactical moves that signal desperation.

The party is at a turning point. Republican stalwarts opposed to Trump remain fearful of the damage the unconventional and unruly billionaire might inflict on the party’s down-ballot candidates in November. But many also now see him as the all-but-certain nominee and are exhausted by the prospect of a contested July convention, according to interviews this week with more than a dozen party figures from coast to coast.

“People are realizing that he’s the likely nominee,” said Tim Pawlenty, a former Minnesota governor and onetime endorser of Sen. Marco Rubio of Florida. “The hysteria has died down, and the range of emotion is from resignation to enthusiasm.”

In Colorado — where Cruz outfoxed Trump in a series of clamorous meetings earlier this month to win all of the state’s 34 available delegates — former state party chairman Dick Wadhams said, “Fatigue is probably the perfect description of what people are feeling.”

Republican presidential candidate Donald Trump told the media he considers himself the party's "presumptive nominee," following five primary victories Tuesday. (Reuters)

He continued: “There is an acceptance, a resignation or whatever, that Trump is going to be the nominee. More and more people hope he wins that nomination on the first ballot because they do not want to see a convention that explodes into total chaos. People just want this to be over with — and we need a nominee.”

[Trump rolls to crushing victories in five East Coast primaries]

With likely Democratic nominee Hillary Clinton pivoting to a general election and her well-funded allies readying for a full-out assault, Republicans are eager to unite quickly. Some are fearful that waiting until the convention in Cleveland to pick a nominee would put the party at a disadvantage in raising money and engaging the Democrats.

“The lion’s share of Republicans want the process settled,” said Mike Dennehy, a veteran New ­Hampshire-based party strategist. “There’s anxiety setting in about the process, and that’s what people are tired of. They just want it done, they want the fighting to stop, and they want a general-election campaign to begin in a meaningful way.”

So does Trump. Celebrating his sweep in Tuesday’s primaries, he declared himself the “presumptive nominee.” At a rally the next day in Indianapolis, he proclaimed, “We’re just about ready to put it away, folks.”

Cruz is pushing back on the idea that Trump is nearing a lock on the nomination. He took the unusual step Wednesday of choosing a running mate, businesswoman Carly Fiorina. The new ticket, as well as independent groups opposed to Trump, see Indiana’s primary on Tuesday as their best — and perhaps last — chance to derail the front-runner and deny him the nomination.

Opposition to Trump still runs strong in parts of the GOP establishment. Former Florida governor Jeb Bush, a vocal Trump critic and former presidential candidate, praised Cruz’s pick of Fiorina in a CNN interview that aired Thursday — in part because he said “she takes on Trump really well.”

Speaking at a campaign rally in Evansville, Ind., April 28, former Indiana men's basketball coach Bobby Knight said Republican front-runner Donald Trump will be one of the four greatest U.S. presidents. (Reuters)

Speaking to reporters Thursday in Fort Wayne, Ind., Cruz predicted that Trump will not win the majority of delegates — 1,237 — and blamed the mainstream media for bestowing what the senator considers a false sense of inevitability on Trump’s campaign.

“Donald, sadly aided and abetted by media network executives who are all liberal Democrats, who are all rooting for Hillary, are quick to say that the race is over,” Cruz said.

[Indiana looms large for Cruz, while options to stop Trump dwindle]

The race is not over, but both Cruz and Ohio Gov. John Kasich are already mathematically eliminated from clinching the nomination on a first ballot and would need a convention floor fight to win. Trump has won 992 of the required 1,237 delegates so far, according to the Associated Press. Cruz has 562, and Kasich has 153. If he falls short, Trump could persuade unbound delegates to lift him over the threshold on the first ballot at the convention.

“Trump has become a fact rather than a problem,” said Newt Gingrich, a former House speaker who has offered informal advice to Trump but has not endorsed him. “Show me mathematically how you’re going to stop him. This all assumes, by the way, that the guy who wrote ‘The Art of the Deal’ can’t figure out a way to make a deal with the undecided delegates.”

Republican consultants across the country are singing the same tune. Reed Galen in Southern California said: “Is it a done deal? It’s certainly looking that way.” In Georgia, Tom Perdue said, “If you go to barbershops in Atlanta, you’ll hear people say they never thought he’d end up being the nominee, but for the most part people think he will be the nominee.”

On Thursday, Trump’s top campaign adviser, Paul Manafort, was on Capitol Hill to meet with lawmakers and press his case that Trump is becoming the de facto GOP standard-bearer.

Two prominent GOP establishment congressmen — Bill Shuster of Pennsylvania, who chairs the House Transportation Committee, and Jeff Miller of Florida, who chairs the House Veterans’ Affairs Committee — endorsed Trump on Thursday.

“It’s time for our party to unite behind Donald Trump and focus our time and energy on defeating Hillary Clinton,” Shuster said in a statement.

[At RNC meeting, some elites aren’t quite convinced by Trump charm offensive]

That echoes what Florida Gov. Rick Scott said Wednesday in a Facebook posting calling for an end to the “Never Trump” movement among conservatives: “Donald Trump is going to be our nominee, and he is going to be on the ballot as the Republican candidate for President. The Republican leaders in Washington did not choose him, but the Republican voters across America did choose him. The voters have spoken.”

Brian Ballard, a Florida-based lobbyist whose clients have included Trump’s real estate company and who also was a top fundraiser for the Bush and Rubio campaigns, said many donors in his state are ready to give to Trump and the Republican National Committee for the general election.

“I think he has earned the nomination, as far as I’m concerned,” he said of Trump. “The folks that I talk to are moving towards him rapidly, though there’s going to be holdouts till the very end who are bitter about what happened.”

At last week’s RNC meeting in Hollywood, Fla., many party officials seemed resigned, if not thrilled, with the idea of Trump as the GOP candidate.

“More and more Republicans are believing that Trump is the inevitable nominee,” said Ron Kaufman, an RNC member from Massachusetts who is close to 2012 nominee Mitt Romney and former president George H.W. Bush. “They’re accepting the fact that he’s the nominee and looking forward to moving on.”

Sean Sullivan in Fort Wayne, Ind., contributed to this report.