Washington CNN  — 

Republican Sen. Mitt Romney did something on Wednesday that he hadn’t done in a quarter century in politics. By voting guilty on the first article of impeachment against President Donald Trump, Romney took a position that was wholly out of step with his party or his raw political self-interest.

It’s true that Romney has been publicly critical of Trump since the 2016 election and only a nominal ally of the White House since entering the Senate last year. But in the years before Trump’s takeover of the GOP, Romney operated less as a paragon of ideological principle and more as a political chameleon – willing to be whatever he needs to be in any given moment.

His journey from a Massachusetts moderate to a conservative businessman to an elder statesman may have kept Romney afloat as a political figure, but it also contributed to his reputation as an inauthentic opportunist – tacking in whatever direction he felt the party was headed.

With his guilty vote, that’s no longer the case.

Once the definition of the Republican establishment, Romney is now, in the era of Trump, the one thing it was hard to imagine he’d ever be: a GOP maverick.

A political chameleon

Since his first bid for office, a failed 1994 run for Senate against Massachusetts Democrat Ted Kennedy, Romney gained a reputation as a political shape-shifter. In that race against Kennedy, the devout Mormon adopted a pro-choice stance on abortion that was still viable for northeastern Republicans.

Eight years later, fresh off saving the troubled Salt Lake City Olympic Games, Romney cast himself as a non-ideological outsider and problem-solver in the tradition of Massachusetts’ moderate GOP governors. By 2005, as he was considering a future run for the White House, Romney announced he was now opposed to abortion and supported the overturning of Roe v. Wade. Facing the prospect of losing the governor’s mansion, he declined to run for a second term in 2006.

In vying for the Republican nomination in 2008, Romney cast himself as a social conservative, a family man, and a pragmatic businessman. It was a flagrant attempt to distinguish himself from his more moderate rival (and eventual nominee) John McCain – the original GOP maverick. But the surprise rise of Mike Huckabee, who won the heavily evangelical Iowa caucuses, put the squeeze on Romney.

Mitt Romney during a 2012 campaign town hall meeting in New Hampshire.

Four years later, Romney was better positioned to be the GOP’s heir apparent. But the party’s base had begun to move in a more conservative and populist direction, and Romney moved right with them.

Besides proclaiming himself “severely conservative” at the annual Conservative Political Action Conference in 2012, the one-time moderate Republican took a harder line on immigration and selected Paul Ryan, a deficit hawk pushing for entitlement reform in Congress, as his running mate.

He even awkwardly accepted the endorsement of the right-wing populist-celebrity-in-chief, Trump.

Now, Romney has been disinvited by CPAC and has become the target of venom from Trump and his allies in the conservative movement.

A Republican backlash

For a man who has appeared overly focus-grouped and airbrushed throughout his career, during his speech on Wednesday Romney came across as unvarnished and authentic.

“My faith is at the heart of who I am,” he said, taking a long pause in which he appeared to be overcome with emotion before continuing. “I take an oath before God as enormously consequential.”

Romney acknowledged the political pressure he would face because of his vote.

“In the last several weeks, I have received numerous calls and texts, many demanding, in their words, I ‘stand with the team.’ I can assure you that that thought has been very much on my mind,” he said. “I support a great deal of what the President has done. I have voted with him 80% of the time.”

Mitt Romney (R-UT) rides in a U.S. Capitol elevator to cast a guilty vote during the Senate impeachment trial.

That may be, but Romney is now more isolated than ever within the GOP. Many of his Republican Senate colleagues responded to his decision respectfully. But even his fellow Utahn, Republican Sen. Mike Lee, felt the need to tweet “congratulations” to Trump for his acquittal and took a thinly veiled swipe at Romney.

“Those who voted to remove you were wrong. Very wrong,” Lee wrote.

Others were even less forgiving.

His own niece, Republican National Committee chairwoman Ronna Romney McDaniel, tweeted that she “disagreed” with her uncle and reiterated that she and the party stand with Trump. The RNC sent out a press release knocking Romney. White House press secretary Stephanie Grisham dismissed Romney as a “failed Republican presidential candidate” in her statement Wednesday afternoon.

There was one aspect of Romney’s vote that was true to form:

“I’ll give him this: professional rollout,” one GOP Senator told CNN. “Not very collegial, but very professional.”

Romney’s vote was proceeded by embargoed print and TV interviews – which built anticipation for his vote, but also irked his colleagues.

If there’s one defining characteristic of Romney’s political career it’s his veneer of professionalism. He always looked the part, and his campaigns were efficient and drama-free – to a fault sometimes. The effect was often that what looked good on the surface looked good, felt artificial underneath.

The big difference now in his polished presentation is that there’s no doubt it’s the real Romney.

CNN’s Phil Mattingly and Lauren Fox contributed to this story.