Voting in the 2024 GOP presidential race kicked off this week in Iowa, but to many Republicans who have been sitting on the sidelines, Donald Trump has already won. Now, they simply have no choice but to endorse his presidential campaign against Democrat Joe Biden.

That kind of highly partisan rationale worked for Trump in 2016 after the release of the “Access Hollywood” tape, and it’s working for him now as establishment GOP officials again rally to his cause even though he sought to overturn an election he lost, culminating in the violent Jan. 6 insurrection and his pledge to build a second term around seeking revenge.

A growing number of Republicans are also choosing to ignore several other alternatives who are still in the race, including former U.N. Ambassador Nikki Haley and Florida Gov. Ron DeSantis, who would almost certainly push for the same policies as Trump if elected, like tax cuts, deregulation and tougher immigration policies.

On X, formerly Twitter, Sen. Mike Lee (R-Utah) voiced his support of Trump on his personal account last Friday.

“Whether you like Trump or not, Americans face a binary choice,” he said. “Biden refuses to enforce our border, prosecutes his opponents, & embraces policies that make life unaffordable for hardworking Americans.”

“I’ll take the mean tweets,” Lee added, referring to Trump’s many unhinged rants online. “I choose Trump.”

Lee didn’t choose Trump in 2016 when he led an effort to deny Trump the nomination during the 2016 GOP presidential convention. He’s since come around to the twice impeached and criminally charged ex-president, even going so far to help push legally dubious schemes to keep Trump in power after he lost to Biden in the 2020 election.

North Dakota Gov. Doug Burgum (R) also called it a “binary choice” between Trump and Biden on Monday during an interview with CNN after he endorsed Trump’s 2024 campaign. Burgum, who suspended his own long-shot presidential bid last month, said the contest is already over because of the ex-president’s overwhelming lead in GOP primary polls.

“In what world is this a binary choice at this point in time with other candidates still in the race?” CNN’s Phil Mattingly responded somewhat incredulously, prompting Burgum to again assert that the Republican primary is all but finished.

“Things might tighten up in New Hampshire, but then you’re going to see across the country that we have never seen this kind of a lead before in a primary. And it’s going to be Trump versus Biden unless the Democrats decide they want to switch horses,” Burgum said.

Trump’s opponents in the race certainly face extremely tough odds. His resounding win in the Iowa caucuses on Monday will only add to the narrative of his unstoppable march to the nomination. He very well may have the nomination locked up by the end of next month, when voters in New Hampshire and South Carolina, two other early nominating states where he leads, cast their ballots.

Republicans who have been sitting out the GOP presidential race so far aren’t stupid and can see which way the wind is blowing. But that doesn’t mean they don’t have other options, as National Review’s Jay Nordlinger pointed out on X.

Evidence is piling up that they do not.

Over the weekend, two more top Republicans announced their endorsements of Trump: Sen. Jim Risch of Idaho and Sen. Marco Rubio of Florida. That means Trump now has the endorsements of 23 of the 49 Republican senators, and more are expected in the coming days.

Rubio, another former Trump critic who ultimately bent the knee, decided to back Trump for another term, shunning both DeSantis, his home state governor, and Haley, who endorsed Rubio’s 2016 presidential campaign.

Former Illinois GOP Rep. Adam Kinzinger, a fierce Trump critic, said he couldn’t comprehend Rubio’s decision during an interview on CNN on Monday, especially since he isn’t facing reelection until 2028.

“And I have no clue why. Like you’re a U.S. senator,” Kinzinger said. “These people used to be strong, independent people. Why do you feel the pressure to endorse now? Why does Marco feel like he’s under such pressure to endorse Donald Trump? I mean, I don’t know when he’s up again, but he’s probably got some time in the Senate. It blows my mind. But there’s this like fear now.”

Republicans who are deciding whether to endorse Trump now, fairly early in the primary calendar, versus later on during a general election, may be making the calculation that they would rather avoid his attacks or the wrath of his supporters.

But Haley, campaigning Monday in Iowa, told caucus-goers to show “courage” before casting their ballots, warning that those who side with Trump may come to regret their choice in the general election.

After finishing a disappointing third place in the caucuses, Haley framed her campaign as the best way of averting a binary between Trump and Biden, saying that “70% of Americans don’t want another Trump-Biden rematch.”

“Our campaign is the last best hope of stopping the Trump-Biden nightmare,” she said.