McGee's decision, after three years on the job, throws wide open the question of who his successor will be. Already, amid dissatisfaction among Democrats that the party has not been aggressive enough in opposing Republican Governor Charlie Baker, a handful of party activists were lining up support for a potential challenge to McGee, who is also a Lynn state senator.

"I have decided not to seek reelection to the position of chair of the Massachusetts Democratic Party," McGee said in an e-mail to members late Sunday.

State Democratic Party chairman Thomas McGee told state committee members Sunday he would not seek a second term, clearing the way for an unusually wide open race for the party's top post.


Governor's Councilor Eileen Duff, former lieutenant governor nominee Stephen J. Kerrigan, and former Fitchburg mayor Lisa Wong have been calling state committee members to check on support they could expect to receive. McGee's exit is likely to hasten that process and could entice additional candidates.

The state committee is set to vote on its next leader at a Nov. 14 meeting.

State Democrats have struggled in the Baker era, often appearing daunted by the governor's impressive poll numbers. Elected Democrats rarely criticize the governor.

And, largely operating in a power vacuum after eight years of former governor Deval Patrick controlling the party apparatus, Democratic Party activists have squabbled among themselves.

Reflecting a larger, national division within the party, Massachusetts Democrats were split during the presidential primary between eventual nominee Hillary Clinton and US Senator Bernie Sanders. Clinton narrowly won the March state primary, but rifts have lingered.

Last month, state Senator Jamie Eldridge, McGee's legislative colleague, e-mailed a list of top Sanders supporters urging them to "take over" the state party and help unseat incumbent legislators, an unusual breach of political etiquette.


On Friday, Jason Cincotti, the party's executive director, declined to comment on rumors that McGee was planning to run next year for mayor of Lynn.

Jim O'Sullivan can be reached at jim.osullivan@globe.com. Follow him on Twitter @JOSreports.