What once sounded like President Trump's nightmare in the Senate — a Sen. Mitt Romney — now seems like much less of a threat.

That's not because Romney, who is running for an open Senate seat in Utah, is expected to lose his primary — though we can't rule that out after he didn't win his party's nomination outright this weekend at the Utah GOP convention. It's more because Romney has had to totally neutralize his Trump criticism to get back into politics.

This is Trump's Republican Party, and Romney's Senate candidacy is one of the more extreme examples of that new reality.

Witness the Romney transition on Trump from the presidential campaign to now. Almost exactly two years ago, Romney was warning his party and the nation of how a Trump candidacy could severely harm the country and the world: "[L]et me put it very plainly. If we Republicans choose Donald Trump as our nominee, the prospects for a safe and prosperous future are greatly diminished.”

Today, he's refusing to criticize the president as he runs for Senate in Utah. “I'm not going to look backward,” Romney said recently by way of explanation.

This is not your average politician flip-flop. As The Fix's Aaron Blake pointed out shortly after the campaign, Romney didn't have to say unkind things about Trump like Republican Sens. Marco Rubio (Fla.) and Ted Cruz (Tex.) arguably did. He wasn't running for president against Trump. Romney chose to speak of his own volition, from his own conviction, that Trump was the exact wrong person for the job.

If Romney still feels that way, he doesn't have the luxury anymore to say it. That was clear when Romney dined with Trump days after the election in search of a secretary of state job.

And that was driven home Saturday at the Utah Republicans' annual convention. There, Utah Republican insiders and party leaders narrowly voted for a state representative, Mike Kennedy, to represent their party in the U.S. Senate race over Romney.

The close result means Kennedy and Romney will compete again in a primary for all Utah Republican voters in June. It's a setback for Romney. Even though Romney handily won the state when running for president in 2012, some Utah Republican leaders aren't quite ready to accept him as one of their own. (The last elected office Romney held was as governor of Massachusetts.)

As The Washington Post's David Weigel reports, you can't separate out Romney's past title as Trump Critic in Chief with Utah Republicans' skepticism of Romney two years later. Trump endorsed Romney, as did Utah's outgoing senator, Orrin G. Hatch, who has been a Trump ally. But since then, Weigel writes:

Trump has solidified his support with Utah Republicans. …. At the convention, Romney never mentioned Trump’s name. He focused instead on his work saving the 2002 Olympics in Salt Lake City and on conservative issues where he aligned with the president.

Some caveats: Trump isn't the only reason Romney supporters say he struggled in the convention. And struggling at Utah's GOP convention may not carry the same warning sign as other state party conventions might.

As Weigel reports, over the past decade or so, at least three Senate or gubernatorial candidates in the state — including outgoing Hach — fell short of the 60 percent vote needed among delegates to be the Republican nominee. Two of those went on to win their primaries anyway.

But it's still remarkable that even in Utah, a state that was extremely skeptical of Trump during the presidential election, opposing Trump now appears to be a political liability. And that means if Romney does win the primary and then November's general election and becomes Utah's next senator in 2019, don't expect him to come to Washington and be the Trump critic he originally was.