It’s Mitt Romney’s big moment, again.

The 2012 Republican presidential nominee has for a year been a freshman senator from Utah. He’s sitting in judgment of the president he has called unfit for office. And he’s defying President Donald Trump by calling for one witness in particular, former national security adviser John Bolton, as the Senate weighs the impeachment allegations against the nation’s 45th president.

The trial is a chance for Romney to wield influence in the Senate as an independent GOP voice — or become one of the Republicans standing by the president when it’s time to be counted. For now, the Utah senator has been clear about wanting more than the manuscript of Bolton’s book, which alleges that Trump directly linked the release of military aid to Ukraine’s willingness to investigate Democrats.

“I’d rather hear from Mr. Bolton,” Romney, 72, told reporters Tuesday.

He may yet get the chance. On Tuesday night, Senate Majority Leader Mitch McConnell told Republicans in a closed session that they lacked the 51 votes to block the 100-member Senate from calling any witnesses. A motion to call them would pass if Romney and at least three other Republicans voted with all Democrats.

It’s far from clear whether Bolton or other witnesses end up testifying before the Senate, or whether Romney, in the end, votes with other Republicans to acquit Trump. Right now, Romney is focused on witnesses, not party, said Jason Perry, director of the Hinckley Institute of Politics at the University of Utah.

“I don’t believe that he believes he has broken ranks with the party,” Perry said. “I believe he thinks he is helping the party, because he believes he is fulfilling the constitutional role of being an unbiased juror.”

The vote math is one of the factors that makes impeachment a rich opportunity for Romney to elevate his status as a rare independent voice in the Trump-dominated Republican Party. Another is the fact that Romney is as safe as a Republican can be under the payback-loving president. He isn’t up for reelection for nearly five years.

Utah is polarized over Trump, but not between Republicans and Democrats. Even as “Never Trumpers” have faded nationally, a strong current of discomfort with the president remains in polite, immigrant-welcoming Utah.

Also, Romney has survived Trump’s attacks, some profane, before. Trump used crude terms to describe Romney’s appeal for an endorsement in 2012. In the heat of the 2016 GOP presidential primary, Romney delivered a speech in which he said Trump “lacks the temperament to be president,” is a “fraud” and, on an assortment of issues, “very, very not smart.”

Trump never forgot it. Victory in hand over Democrat Hillary Clinton, Trump said he was considering nominating Romney for secretary of state. Romney met him for an awkward dinner that produced awkward photographs. Later, Trump said he never really considered Romney for the post.

“Mitt Romney never knew how to win. He is a pompous ‘ass’ who has been fighting me from the beginning,” Trump tweeted last year.

Asked last week whether he can really be unbiased after that last crack, Romney dismissed it as irrelevant.

Going against Trump is “a risk for any Republican. Mitt Romney is familiar with that. He can handle it,” said Sarah Longwell, executive director of Republicans for the Rule of Law. She said the group is spending more than $1 million on ads this week calling for witnesses.

But in contrast to the ads in places like Colorado, where Republican Sen. Cory Gardner is in a tight reelection race, the ads running in Utah aren’t focused on just Romney, Longwell said. One goal, she said, is to “educate his constituents” on why he wants witnesses to testify.

“This is Ambassador John Bolton,” intones the narrator over a photo of Bolton with his mouth taped shut. “Are Senate Republicans willing to do their duty to listen?”

There’s been a bit of blowback.

Sen. Kelly Loeffler, R-Ga., tweeted Monday that Romney “wants to appease the left by calling witnesses who will slander” the president.

Inside the Senate, Romney is part of the whip, or vote-counting, team. But there’s scant evidence that he’s giving, or getting, any lobbying about witnesses. After the defense rested on Tuesday, Senate Republican whip John Thune ambled over to Romney’s seat in the back row, two chairs from the corner, just before the big meeting in McConnell’s office. The two chatted for a few seconds.

The president’s defense team has showed little if any interest in pressing Romney on the Senate floor. And an official close to the senator said there is no lobbying effort afoot on Romney’s part.

Romney’s conduct in the chamber would seem to support that. He’s mostly sat, or stood by his chair, taking notes and occasionally chatting with seatmates Mike Braun of Indiana and Dan Sullivan of Alaska.

Romney is famously a sticker for rules. Technically, only water and milk are allowed on the Senate floor. On Tuesday, Romney was seen with a bottle of chocolate milk, from the Brigham Young University creamery. But a bottle is against the rules. He was later seen with what looked like chocolate milk in a glass.

(AP)