Here are some of the key takeaways from Tuesday's Massachusetts primary

Several Massachusetts office-holders lost their reelection bids at the primary stage Tuesday, an unusual trend in a state where incumbents typically enjoy major advantages.

Two sitting state representatives, Democrat Rep. Rady Mom of Lowell and Republican Rep. Susan Williams Gifford of Wareham, fell short against primary challengers. Another, Cambridge Democrat Rep. Marjorie Decker, is trailing by a paper-thin margin in a race that had not been officially called by lunchtime Wednesday.

And in the Governor's Council, 25-year veteran Marilyn Petitto Devaney lost her reelection bid to public defender Mara Dolan.

If Decker's loss becomes official, three legislative incumbents will have been tossed from office by voters. That may seem like a small total, but only 18 sitting lawmakers across both branches and both parties faced any primary opposition at all.

Two years ago, former Rep. Marcos Devers was the only sitting lawmaker to lose in a primary. The cycle before that, two lawmakers lost to primary challengers, one of whom -- Rep. David Nangle of Lowell -- had been indicted months earlier on federal fraud charges.

Would-be contenders might look at Tuesday's results with regret since the results show some voters were open to change. Continuing a years-long trend, most House and Senate districts feature no competition this election season.

In Cambridge, six-term Rep. Decker appears to trail first-time candidate Evan MacKay by a small margin, according to votes counted so far. Unofficial results from the city show MacKay winning by 40 votes -- just about half a percentage point -- though the contest still has not been officially called by the Associated Press, and officials say some hand-counted ballots were not included into the online tally.

MacKay, a labor organizer and Harvard teaching fellow, claimed victory Tuesday night after spending much of the campaign criticizing "dysfunction" on Beacon Hill and calling for changes to improve the Legislature's transparency, concentration of power and work culture.

"This was a campaign where some of us from the very beginning had a belief in the impossible," MacKay told supporters Tuesday night, according to Cambridge Day. "We showed that a grassroots movement can take on the might of the political establishment and we can win."

Decker was first elected in 2012 and has cruised to five more terms since then. She has not faced any opponent since the 2018 primary, which she won with 85 percent of the vote.

She's been a visible figure on Beacon Hill, this session co-chairing the Public Health Committee and leading the House's negotiating team on maternal health legislation that Gov. Maura Healey signed into law Aug. 23, less than two weeks before the primary.

Reflecting on Decker's influence, former Speaker Robert DeLeo said in 2019, "Some of the other members have joked with me at times and stated, 'How do we get a bill passed around here? Do we have to ask Marjorie Decker or you?'"

Her defeat would be one of the higher-profile Democratic primary losses in recent cycles. Other urban Democrats in high-ranking positions have succumbed to challenges from their political left. Former House Ways and Means Committee Chair Jeff Sanchez and former Assistant House Majority Leader Byron Rushing both lost to challengers (former Reps. Nika Elugardo and Jon Santiago, respectively) in 2018.

It was not immediately clear if Decker would pursue a recount. She did not return a call seeking comment Wednesday.

Another legislative race might also be bound for a recount.

With 99 percent of votes counted in the Republican primary for an open Senate seat, the AP reported that Rep. Mathew Muratore of Plymouth led Kari MacRae of Bourne by 48 votes. A party source said a recount in that race appears likely, though Muratore declared victory Wednesday morning.

"While the final handful of votes remain to be counted, we are confident in our lead, and -- most importantly -- we are grateful to the voters that put their trust in our campaign," Muratore said in a statement. "As a Republican, I believe in democracy and healthy competition, and I congratulate my Republican challenger, Ms. MacRae, on her spirited campaign. The focus of my campaign has now shifted to the November general election."

Muratore never faced a primary opponent in his five successful House campaigns, and he's now locked in a nail-biter against a candidate to his right. MacRae, a member of Bourne's School Committee, was fired from a job teaching at Hanover High School in 2021 over TikTok videos she previously posted commenting on critical race theory, gender identity and other topics. A federal appeals court upheld her termination as valid.

Whoever emerges victorious in that primary will face Democrat Rep. Dylan Fernandes of Falmouth in the general election. Republicans are trying to flip the purple Senate seat currently held by Democrat Sen. Su Moran.

In the close races, candidates have until the end of the week to decide whether to pursue a recount. The deadline to file a petition for a district-wide recount is 12 p.m. Friday, and the deadline to file a petition for a precinct-level recount is 5 p.m. Friday.

A Republican challenger defeated another long-time GOP state rep in southeastern Massachusetts.

Eleven-term Rep. Susan Williams Gifford of Wareham, the third assistant minority leader in the House, lost handily to challenger John Robert Gaskey of Carver. It was the first time Gifford faced a primary opponent since her first election in 2002.

Gaskey portrayed himself as an "outsider" and cast Gifford as "a 20-year-incumbent who has mostly 'gone along to get along' with the Democratic majority." He staked out positions opposing gender-affirming care, likening LGBTQ+ education in schools to "brainwashing children" and slamming state spending on shelter for newly arriving migrants.

The third incumbent lawmaker who tumbled to defeat Tuesday is Mom, who in 2015 became the first Cambodian-American elected to a state legislature in the United States.

Another Cambodian-American, Tara Hong, bested Mom in a three-way Democratic primary -- a quasi-rematch of 2022, when Hong unsuccessfully challenged for the seat.

Hong pledged to focus on constituent services, increase transparency on Beacon Hill including by making all votes public records, and help to craft a plan for fixing the Rourke Bridge, which was built in 1983 as a temporary span but remains in use today.

The incoming freshman is bound to hold one superlative: Hong, now 24, is poised to become the youngest member in the House. The current youngest representative is Ryan Hamilton of Methuen, who according to the House clerk's office is 26.

But Hong will not become the all-time record-holder: per the House clerk's office, former Rep. Thomas Lussier of Pittsfield was born April 5, 1957 and served from 1977 to 1984.

Hong, Gaskey and, if the race gets declared, MacKay would all be effectively guaranteed spots in the House next term because they do not have major-party opponents in the general election.

Voters picked six other de facto new lawmakers Tuesday, all Democrats who do project to face opposition in November. Rep. Bill Driscoll of Milton won a primary for the Senate seat being vacated by Sen. Walter Timilty; Thomas Moakley of Falmouth won a primary for the House seat Fernandes is giving up; Sean Reid of Lynn won a primary for the House seat held today by Rep. Peter Capano; Greg Schwartz of Newton won a primary to succeed retiring Rep. Ruth Balser; Hadley Luddy of Orleans was the only candidate on the ballot for the House district represented by Rep. Sarah Peake, and so was Homar Gomez of Easthampton in a bid to replace Rep. Daniel Carey.

A Democrat will push to keep a Senate seat both blue and also represented by a Pacheco. Raynham Selectman Joseph Pacheco beat Taunton City Councilor Barry Sanders in the primary to succeed retiring Sen. Marc Pacheco (no relation). He'll face Republican Taunton City Councilor Kelly Dooner in November.

In the Governor's Council, Dolan pulled off what she narrowly failed to do two years ago: unseat Devaney, a veteran incumbent who has held the position for 25 years.

The Associated Press called the Democratic primary rematch for Dolan around 1:30 a.m. Wednesday. No other candidates are on the ballot, so Dolan is effectively guaranteed to become the first new councilor for the district since the Clinton administration.

"We did it!!!" Dolan posted on X just after 2 a.m. "Thanks to everyone who worked so hard on this campaign. I am incredibly proud to be your Democratic nominee."

Dolan says she will become the first public defender on the council, whose primary task is to vet and confirm nominees for judgeships, Parole Board and clemency.

Devaney has often been involved in some of the panel's internal sniping, and four of her colleagues -- a majority of the current panel, which is down a member -- endorsed Dolan days before the primary.

In another council race, Tamisha Civil of Stoughton topped a four-way Democratic primary for an open seat. The Council's Second District, which stretches south of Boston, has been vacant for the entire term. Former Councilor Robert Jubinville won reelection in 2022, but resigned about a month later for a job as clerk magistrate of Framingham District Court.

Jubinville then challenged for Norfolk County clerk of courts in Tuesday's primary, but he told the News Service he lost to Sen. Walter Timilty III, who would succeed his father in the job.

Voters on Tuesday also picked John Deaton as the Republican nominee to face U.S. Sen. Elizabeth Warren and effectively filled several open seats in the Legislature where no major-party opponent looms in November.