IT’S BEEN THE latest political parlor game to hit the presidential sweepstakes: Will former Massachusetts governor William Weld jump into the race and, if so, will it be as a candidate of the Libertarian Party he recently swore lifelong fealty to or as an insurgent Republican looking to dislodge an incumbent president?

We now know the answer at least to the party question: If Weld runs, he’ll do so as Republican. The town clerk’s office in Canton, where he lives, said Weld showed up at Town Hall on January 17 and changed his party registration from Libertarian to Republican.

That is sure to stoke speculation over whether Weld is preparing to mount a long shot challenge to President Trump for the Republican nomination next year. Trump has abysmal approval numbers, and he’s as incurious about briefing papers and policy substance as he is eager to engage in name-calling Twitter attacks on rivals and one-time aides.

But few see an opening for a primary challenger in a party that has tacked sharply to the right and is now viewed as firmly under the control of a president who has appeased the hardcore GOP base with his stands on everything from immigration to abortion and gun rights.

Weld, elected to two terms as a Republican governor in the 1990s, has long identified with a strain of Northeast Republicanism that is all but gone today: Fiscal conservatism combined with progressive stands on many social issues, including gay rights and abortion rights.

Weld, who is a partner in the lobbying firm ML Strategies, did not respond to an email late Monday afternoon asking about his party switch and potential presidential plans. He’s scheduled to deliver a speech next week in New Hampshire.

To say Weld has not shown particular fidelity to his Republican roots – or to any party label or fixed ideology – would be like saying the Rams did not show tremendous success advancing the ball in yesterday’s Super Bowl.

After being elected governor twice as the state’s Republican standard-bearer, Weld endorsed Barack Obama in 2008 before pivoting back to support his party’s nominee, Mitt Romney, when Obama ran for reelection four years later. In 2016, Weld jumped ship from the GOP entirely, signing on with the Libertarian Party and running as its vice presidential nominee – though that didn’t stop him from offering lots of encouragement for Hillary Clinton in the closing days of the race.

Weld’s sudden Libertarian conversion was met with skepticism among die-hard faithful of the party of less government. He sought to assuage their doubts with an ironclad declaration at the party’s May 2016 nominating convention in Orlando, Florida. “If you hear nothing else from me, hear this: I pledge to you that I will stay with the Libertarian Party for life,” Weld told delegates as he eked out a narrow victory to become presidential nominee Gary Johnson’s running mate. He had switched his party registration from Republican to Libertarian only three months earlier, in February of that year.

Word of Weld’s return to the Republican fold was greeted with some doubts.

“It would be wonderful to have a moderate Republican running against Trump to give other voters in a Republican primary someone to vote for,” said Jennifer Nassour, a former chair of the Massachusetts Republican Party and Trump critic. “The downside for Weld is he left the party and party voters, whether a Republican or Democrat, don’t look too kindly on someone who leaves the party and comes back.”

Even those without Weld’s party-switching baggage have not had much success challenging an incumbent president from their party.

Weld may reveal more about his plans on February 15 when he speaks at the Politics & Eggs series, a partnership of the New England Council and St. Anselm College that has become a required stop for those contemplating a run in the state’s first-in-the-nation primary.