Sen. Ted Cruz’s decision to support Donald Trump after months of holding out is dividing even members of his former campaign team, with some observers pointing to his 2018 re-election race and a possible 2020 presidential bid as underlying factors.
The about-face — after Mr. Cruz told Republican delegates to vote their “conscience” at the party’s national convention in July — also came after Republican National Committee Chairman Reince Priebus said the party could make it more difficult for such holdouts to run for office and as talk of a possible primary challenge to Mr. Cruz in 2018 has surfaced.
“Whatever path I went down, there were going to be people who were dismayed,” Mr. Cruz said at the Texas Tribune Festival over the weekend. “There was no option that wouldn’t result in people being deeply, deeply unhappy.”
He said he doesn’t know the political repercussions and is “not smart enough to figure that out.”
“I’m trying to do the right thing: follow my conscience. What is right for this country? And my view, from the beginning, is do what’s right, stick to your principles, and the politics [will] work out,” he said.
Mr. Cruz has cited Mr. Trump’s new commitment to nominate Supreme Court justices only from a specific list of 21 names — a list that now includes close friend and ally Sen. Mike Lee of Utah — as a key factor in his decision.
“This commitment matters, and it provides a serious reason for voters to choose to support Trump,” Mr. Cruz said in a statement on his Facebook page announcing his decision.
Mr. Cruz said Mr. Trump has not apologized to him for attacks on his family. He said in July that the attacks voided the pledge he made last year to support the eventual Republican presidential nominee.
During the primary campaign, Mr. Trump threatened to “spill the beans” on Mr. Cruz’s wife, Heidi, shared an unflattering image of Mrs. Cruz next to one of his own wife, Melania, and drew a connection between Mr. Cruz’s father, Rafael, and the assassination of President John F. Kennedy.
“At the end of the day, it’s not about me. It’s not about my family. It’s about the country,” Mr. Cruz said.
Alice Stewart, who was communications director for Mr. Cruz’s presidential campaign, said some are understandably dismayed, but that it’s effectively a choice between Mr. Trump and Democratic nominee Hillary Clinton at this point.
“There’s clearly a lot of hard-core conservatives that are not going to be happy with news, understandably,” Ms. Stewart said on CNN. “This is where they come from. This is their core.
“For the furtherance of the conservative cause right now, it’s in everyone’s best interest to get behind Donald Trump,” she said.
But Rick Tyler, who was another top spokesman for the Cruz campaign, said, “It’s mourning in America for conservatives.”
“We lost our leader today,” Mr. Tyler told NBC News.
Liam Donovan, a conservative columnist and “never Trump” adherent, said Mr. Cruz was making a bet two months ago that Mr. Trump would be on his way to a loss at this point.
“He is recalibrating based on the very real possibility that Trump could win, as well as a degree of blowback at home and nationally that I don’t think he fully anticipated,” Mr. Donovan said. “So he is selling off his short position at a political loss. The only question now is how long he goes and whether the bet pays off.”
Dean Ouellette, a Marco Rubio turned Cruz supporter from Arizona, said Mr. Cruz saw an opportunity and took advantage of it.
“He’s jumping on an opportunity, and I think he’s making a bad miscalculation because Trump will never welcome him in as a supporter, really, and all the supporters he did have, he’s turning his back on,” Mr. Ouellette said.
“We took a lot of heat from longtime Republican friends because we supported Ted and what he did, and then for him to turn his back on all of us is really disappointing,” he said.
Mr. Ouellette said he won’t vote for either Mr. Trump or Mrs. Clinton and is leaning toward supporting independent conservative candidate Evan McMullin.