Gov. Charlie Baker, a moderate Republican in a state dominated by Democratic officeholders, confirmed on Tuesday he will seek a second four-year term, a decision that had been widely expected.
On Twitter and later during a previously scheduled appearance in Worcester, Baker said he and Lt. Gov. Karyn Polito will run for re-election in 2018.
"We've accomplished a lot together, but there's more work to do," Baker tweeted.
The official launch of his campaign will not come until after the new year, said Jim Conroy, a senior political adviser who first announced Baker's intention to run again in a statement issued earlier Tuesday.
"With election day still a year away, the governor and lieutenant governor remain focused on the bipartisan work they were elected to do, and a formal campaign launch should not be expected until later next year," Conroy said.
Baker has maintained high favorability ratings in public opinion polls throughout his first term as governor of Massachusetts. He has frequently distanced himself from President Donald Trump and the Republican congressional leadership on issues such as health care and immigration policy.
The governor's campaign will be directed from a headquarters in Boston, and Brian Wynne, executive director of the Massachusetts Republican Party, is expected to serve as campaign manager.
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By delaying a formal announcement until next year, aides say, Baker can avoid directly engaging his political opponents while continuing to raise money and press his legislative agenda.
Baker has maintained a brisk fundraising pace, with his campaign account reporting a mid-November balance of just under $7 million. The three announced Democratic candidates for governor had less than $100,000 combined in their accounts, according to their most recent filings with the state Office of Campaign and Political Finance.
One of those Democrats, former state Secretary of Administration and Finance Jay Gonzalez, took aim on Tuesday at what many political observers view as one of Baker's strengths: his reputation for working cooperatively with Democratic legislative leaders.
"Charlie Baker seems to be confusing bipartisanship with cowardice," Gonzalez said. "Bipartisanship isn't refusing to take a stand, ducking and weaving when faced with big challenges."
Outgoing Newton Mayor Setti Warren and one-time Democratic candidate for lieutenant governor Robert Massie also are seeking their party's nomination.
One Republican, Barnstable County Commissioner Ronald Beaty Jr., said recently he was exploring a run for governor.
Senate President Stan Rosenberg, an Amherst Democrat who has acknowledged a productive working relationship with Baker, said he will support his party's 2018 nominee, regardless of who it is, "because I'm a Democrat" and because the governor "tilts" toward the Republican Party's platform.
Asked to single out an area of sharp disagreement with Baker, Rosenberg cited the governor's refusal to consider new tax revenue sources to support investments in transportation and education.
Baker's first campaign for governor was in 2010, when he lost to incumbent Democratic Gov. Deval Patrick. Baker won the GOP nomination again in 2014 and narrowly defeated Democratic Attorney General Martha Coakley in the general election.