Even as Donald J. Trump trounced him from New Hampshire to Florida to Arizona, Senator Ted Cruz could reassure himself with one crucial advantage: He was beating Mr. Trump in the obscure, internecine delegate fights that could end up deciding the Republican nomination for president.
“This is how elections are won in America,” Mr. Cruz gloated after walking away with the most delegates in Wyoming last month.
Now, as he faces a potentially candidacy-threatening contest on Tuesday in Indiana — where a new NBC News/Wall Street Journal/Marist poll, released Sunday morning, showed him trailing Mr. Trump by 15 percentage points — Mr. Cruz can take little solace from his vaunted delegate-wrangling operation even if he prevails there.
It turns out that delegates — like ordinary voters — are susceptible to shifts in public opinion. And as the gravitational pull of Mr. Trump’s recent primary landslides draws more Republicans toward him, Mr. Cruz’s support among the party’s 2,472 convention delegates is softening, threatening his hopes of preventing Mr. Trump’s nomination by overtaking him in a floor fight.
With each delegate Mr. Trump claims, he gets closer to the 1,237 he needs to clinch the nomination outright, and Mr. Cruz’s chances of stopping him — even with an upset victory in Indiana — shrink.
Before Mr. Trump’s crushing victory in Pennsylvania last week, Mr. Cruz’s campaign boasted that it had 69 people devoted to acquiring as many as possible of the state’s 54 unbound delegates — who are free to vote as they please on the first ballot, making them potentially decisive players in a contested convention.
And in states across the South, which was supposed to be Mr. Cruz’s bulwark, some delegates are now echoing a growing sentiment inside the Republican Party: a sense of resignation to the idea that Mr. Trump will be their standard-bearer.
“Honestly, we didn’t think he could get this far. And he did,” Jonathan Barnett, the Republican national committeeman for Arkansas, said of Mr. Trump. Mr. Barnett, who supported former Gov. Mike Huckabee’s failed campaign, said his focus had shifted to winning in November, even if that meant unhappily falling in behind Mr. Trump.
The changes of heart have little to do with any epiphany about Mr. Trump’s electability or his campaign’s recent efforts to cast him in a more serious light. Instead, delegates and party officials said, they are ready to move on and unite behind someone so that Republicans are not hopelessly divided heading into the general election.
And many delegates cite concerns about whether Mr. Cruz is really a better choice. “There’s just as many people that would question whether they could get behind Cruz,” Mr. Barnett said.
This gradual acquiescence points up a larger flaw with Mr. Cruz’s strategy of being the last non-Trump candidate standing in a field that began at 17: It was never as much about him as about Republicans grasping for a more palatable alternative to Mr. Trump.
But the “never” in the “Never Trump” movement is beginning to look more like a “reluctantly.”
“I’m not in the anybody-but-Trump campaign,” said Jim Poolman, a delegate from North Dakota. “I’m in the anybody-but-Hillary campaign.” Mr. Poolman said he still planned to vote for Mr. Cruz on the first ballot, which he told the campaign he would do. But he said his decision was not set in stone. “I’m trying to hold on to my commitment but still be pragmatic,” he said. “There’s a lot of stuff that could happen before Cleveland. And I know that makes me sound squishy, but I don’t mean it that way.”
Delegates like Mr. Poolman are emblematic of the Cruz campaign’s larger problems holding on to votes at a contested convention.
But now, Mr. Poolman said, he worries about party disunity and what it could mean for Republicans in November. “My goal, personally,” he said, “is to not let our convention become a circus.”
The chairman of the North Dakota Republican Party, Kelly Armstrong, said Mr. Cruz’s appeal remained strong there, but put his support among the state’s 28 unbound delegates at “at least 10” — not quite the “vast majority” the Cruz campaign had claimed.
Mr. Armstrong, who has not taken sides, said delegates also had to consider how denying the nomination to Mr. Trump might look to his supporters. “We can’t have a bunch of people really, really upset about the process and then think we’re going to be able to gain their support in November,” he said.
The results in Pennsylvania were most troubling for Mr. Cruz. He had dominated the delegate fights in Colorado and Wyoming, contests that were influenced by the kinds of party activists Mr. Cruz tends to attract. Yet Mr. Trump appeared to win at least 40 of Pennsylvania’s 54 unbound delegates. “There’s not going to be a second ballot,” said Ash Khare, who was elected last Tuesday as an unbound Pennsylvania delegate. Mr. Khare declined to support any candidate before the election, though Mr. Cruz, Mr. Trump and Gov. John Kasich of Ohio all came calling, he said. “I was promised a photo, a private meeting. Forget about it,” Mr. Khare said, adding that he only ever intended to vote for the candidate who won in his district.
That would be Mr. Trump. Mr. Khare said he was not especially drawn to anything about Mr. Trump or his ideas. “Whether he will succeed or not, I don’t know,” he said. But he said he could not deny the will of so many voters. “There is a revolution going on here,” he added.
Voters may be starting to share Mr. Trump’s reasoning that he would deserve the nomination even if he fell short of 1,237 delegates. A recent NBC News/Wall Street Journal poll found that more than six in 10 Republicans believe the nominee should be the candidate with the most votes even if he does not have the support of the majority of delegates. Still, Mr. Trump’s campaign is moving to nail down the delegate commitments he would need to get a majority.
With the Indiana primary potentially a make-or-break moment for stopping Mr. Trump, Mr. Cruz can only hope the campaign once again takes an unexpected turn. “Trump is very popular in our state,” said Alec L. Poitevint II, a longtime Republican leader in Georgia and previously a Rubio supporter, but now uncommitted. He will be a bound delegate on the first ballot, but he has not yet been assigned to a presidential candidate. And if he is required to vote for Mr. Trump, who won Georgia with 39 percent of the vote?