Massachusetts primary results: Trump-backed challenger wins GOP governor nomination, AP projects

The Associated Press projected Geoff Diehl, who was backed by former President Donald Trump, has won the Republican nomination for governor in Massachusetts. He will face Maura Healey, who the AP projected earlier won the Democratic contest, in November.

Massachusetts is one of the Democrats' best chances at flipping a governor's mansion, since moderate Republican Gov. Charlie Baker is not running for reelection.

Diehl defeated businessman Chris Doughty, a political newcomer, and had been backed by neighboring New Hampshire's moderate Republican Gov. Chris Sununu. 

Baker, who refused to vote for Trump in 2016 or 2020, did not endorse either candidate. 

Healey, the current attorney general of Massachusettes, was running virtually unopposed on the Democrat side. Sonia Chiang-Diaz dropped out of the race in July but her name remained on the ballot.

Healey would be the state's first openly gay governor and the first woman elected governor of the state. Jane Swift in 2001 became the first female governor of Massachusetts when Paul Cellucci resigned to serve as ambassador to Canada, but the following year she lost the Republican nomination to Mitt Romney.

Despite Massachusetts' reputation as a liberal state, only one Democrat, Deval Patrick, has been elected governor since 1990. But most of those Republican governors were considered fiscally conservative and socially moderate. Trump captured just 32% of the vote in the state in 2020, winning about 75,000 more votes than he did in 2016 although roughly the same percentage of the vote. 

Not only has Trump endorsed Diehl, Trump's former adviser Corey Lewandowski is a strategist for the campaign and Diehl was the 2016 state co-chair of Trump's campaign. Diehl also has repeated Trump's baseless claims that the 2020 election was stolen, fought against the extension of mail-in voting , and said he supports the Supreme Court decision overturning Roe v. Wade.

Trump held a phone rally for Diehl on Monday night, saying Doughty would "do nothing but surrender to the left wing."

Diehl unsuccessfully ran against Sen. Elizabeth Warren in 2018, losing by 24 points. 

Doughty, meanwhile, tried to appeal to more moderate voters. Matt Murphy of State House News told CBS Boston ahead of the race that Doughty's chances would come down to independent voters.

"How many of those independents decide to participate in the Republican primary?" Murphy said. "For Doughty to have a chance, he has to draw in a lot of those independents, maybe even the ones who would typically vote Democrat to maybe thwart that Trumpian messaging that's coming from the Republican Party. If a lot of them participate, maybe he can close the gap with Diehl."

There are several Democratic candidates on the ballot for other statewide offices, including to replace Healey as attorney general. Former Boston city councilor Andrea Campbell and workers' rights attorney Shannon Liss-Riordan are both running, having split some of the state's most powerful Democrats for endorsements. Liss-Riordan has the backing of Warren, Boston Mayor Michelle Wu and former acting Boston Mayor Kim Janey, while Campbell has been backed by Healey, Sen. Edward Markey and half the state's congressional delegation.

The winner will face Republican Jay McMahon in November.

None of the state's nine Democratic members of Congress are facing any primary challengers. Neither of the state's two senators are up for reelection this year. 

Polls closed at 8 p.m. ET.

Aaron Navarro contributed to this report.