GOV. CHARLIE BAKER IS increasingly a man without a party.

Four years ago Donald Trump won the Republican presidential primary in Massachusetts with 49 percent of the vote. Now his support among Republicans in Massachusetts is overwhelming.

A WBUR poll of 374 likely Republican primary voters found 82 percent of them have a favorable view of Trump, compared to only 50 percent for Baker, the state’s Republican governor. Baker’s favorability was actually higher, at 61 percent, among 471 Democratic primary voters surveyed separately.

On question after question in the survey of likely Republican voters, whether it was the firing of those who testified against him during the impeachment proceedings or the pardons and commutations of 11 controversial figures, Trump won strong support.

When asked who is the better model for Republican politicians to follow, 63 percent said Trump. Only 27 percent said Baker.

In the Massachusetts Republican presidential primary, it was no contest: Trump received the support of 83 percent of the likely GOP voters; William Weld, Baker’s political mentor, garnered 14 percent support.

“The party here is Donald Trump’s party,” said Steve Koczela, president of the MassINC Polling Group, which conducted the survey for WBUR. “Sometimes it’s harder to see, because Charlie Baker is a Republican governor and is incredibly popular, but when it comes to the committed base of the Republican Party, it is Trump’s party.”

That may explain why a super PAC with close ties to Baker is supporting both Republicans and Democrats in special elections for legislative seats and why it’s backing Republicans who are more in sync with Baker in special election GOP primary fights.

The Massachusetts Majority PAC spent $4,879 on a campaign mailing supporting Democrat Kate Lipper-Garabedian in the Democratic primary race for the rep seat vacated by Paul Brodeur of Melrose. The PAC has also spent $14,025 so far on campaign mailings backing Jesse Brown in his bid to defeat James McMahon III in the GOP primary for the Senate seat vacated by Vincent deMacedo of Plymouth. And the PAC has sent out $7,334 worth of mailings on behalf of Catherine Clark, who is running against Malena Chastain in the Republican primary for the rep seat vacated by Democrat Jennifer Benson of Lunenburg.

Bruce Mohl oversees the production of content and edits reports, along with carrying out his own reporting with a particular focus on transportation, energy, and climate issues. He previously worked...