Carnevale, a longtime lobbyist and state committee member, was first elected chair in 2023, narrowly defeating incumbent Jim Lyons, and won reelection by a wide margin last year. In an email to committee members Monday morning, she called her four years as chair "one of the greatest honors of my life" and said she was proud of what the party had accomplished.

She described inheriting an organization nearly $1 million in debt and out of compliance with the Federal Elections Commission and the Massachusetts Office of Campaign and Political Finance, facing mounting legal expenses, lawsuits, a diminished donor base and infrastructure too weak to operate effectively. Restoring the party, she said, required difficult decisions, disciplined financial management and a renewed commitment from supporters.

Under her leadership, Carnevale said the party resolved all but one outstanding legal matter and stabilized its finances. She pointed to 2024 as a high point, when the MassGOP helped flip multiple seats while defending every seat held by a Republican incumbent and increased support for President Donald Trump in nearly every county.

But she acknowledged that this year was "a particularly demanding election cycle" as the political landscape shifted, including a competitive GOP primary for governor. "Not every effort produced the outcome we had wanted, but our team remained committed to our candidates and continued to provide the support and resources necessary to navigate an unpredictable political environment," she wrote.

The announcement comes after heavy Republican losses in last week's election. Elizabeth Dionne, a former candidate for state treasurer, announced Sunday that she is running for the chair post. In her own message to committee members, Dionne called Tuesday's results "devastating" but said "this is no time to retreat."

"One-party rule hurts us all, so we must organize now to check the super-majority on Beacon Hill," Dionne said, adding that Republicans, independents and "JFK Democrats" across the state have asked for a stronger GOP to counter the Democrats' left flank.

Dionne said fundraising, clear messaging and strategic planning to support successful campaigns should be the party's highest priorities. Citing the party's financial condition, she pledged to serve without a salary for the full two years of her term if elected and called on other candidates to make the same commitment.

The only other candidate to emerge so far is Gene Parini, chairman of the Sandwich Republican Town Committee, who said in September that he planned to run. The state committee is scheduled to elect its next chair in January.

The leadership change comes at a moment when the Massachusetts GOP is trying to remain relevant in a state where Democrats hold overwhelming majorities in the Legislature and every statewide office. How the next chair balances fundraising, message discipline and outreach to unenrolled voters will shape whether the party can mount a credible check on Beacon Hill's Democratic supermajority — a question with consequences for how the state's tax, housing and climate debates unfold.