“Many people told us it couldn’t be done,” Folpe said. “We had the governor against us. We had many members of the state legislature against us. We had unions against us.”

Amid deafening cheers, Folpe spun a canister that hurled colorful streamers into the air.

While Decker did not explicitly admit defeat or call MacKay, she seemed close to doing so when she gave an emotional speech about her time in Parliament.

“There are a lot of tears to be shed. I’m not shedding any,” Decker told supporters at her election party at Fresh Pond Beer Garden. “I’ve spent 25 incredible years doing what I love.”

A loss for Decker would be a major surprise in a state where few incumbents face a serious challenge in the primaries, let alone suffer defeat at the ballot box.

Decker, chair of the legislature’s Joint Committee on Public Health, faced little substantive competition before MacKay decided to challenge her. She has never faced an opponent in the general election, and her last primary was six years ago, in 2018.

Every two years, all 160 House of Representatives districts and 40 Senate districts are up for election, and this year, as in most election cycles, only a fraction of voters had the opportunity to cast their ballots in a contested primary.

Many state representatives and senators faced no opposition this campaign season and easily made it to the November election. Some will face Republican opponents, but others will win without that challenge.

It is a familiar pattern: Between 2002 and 2022, only 25 Democratic candidates for the House of Representatives managed to defeat an incumbent in a primary.

However, there were still several other competitive races throughout the state.

In Somerville, voters gave incumbent state Rep. Erika Uyterhoeven, a democratic socialist, a victory over her challenger Kathleen Hornby, a progressive who previously worked for Decker as a state House staffer.

MacKay made inaction and the lack of transparency on Beacon Hill a central theme of her campaign. Other elected officials endorsed Decker, including some of the state’s leading Democrats such as Governor Maura Healey, U.S. Senator Ed Markey and U.S. Representatives Katherine Clark and Ayanna Pressley, who sent text messages to voters on Decker’s behalf in the days leading up to the election.

Before the unofficial results were announced, Decker’s supporters ate pizza and drank beer at her event, but the mood quickly turned somber as the results from polling stations started trickling in.

The participants hugged each other and cried. Decker walked through the beer garden and hugged every participant who came.

“I’m not going away, believe me,” Decker said in her speech. “I don’t know how to go away.”

Other incumbents who had to face challengers on Tuesday were Democratic State Representatives Francisco Paulino of Methuen, Bud Williams of Springfield, David Linsky of Natick, Jack Lewis of Framingham, Thomas Stanley of Waltham, Rady Mom of Lowell, Joseph McGonagle of Everett, Paul Donato of Medford, Rita Mendes of Brockton, and Russell Holmes and Jay Livingstone of Boston. Republican state Reps. Susan Gifford of Wareham and Paul Frost of Auburn also struggled on the GOP ballot.

On the Senate side, Democrats Mark Montigny of New Bedford, Adam Gomez of Springfield and Nick Collins of Boston faced challenges in the primaries.

Despite the lack of competition, deputies and supporters continued to work hard on Tuesday.

The powerful House Budget Committee chairman Aaron Michlewitz, who himself had no challenger in the primary, touted some of his colleagues. Photos posted on Instagram show him handing out flyers for Decker with the Massachusetts Building Trades Union, holding signs for Donato and calling voters for McGonagle from a camp chair in Everett.

The Bonde Fine Wine Shop in Harvard Square posted a sign reading “They say vote for Marjorie Decker,” and Chrissy Lynch, president of the AFL-CIO in Massachusetts, posted a selfie with Decker while campaigning for the candidate at the polling station.

Collins, the incumbent Democrat in Boston, appeared at Florian Hall in Dorchester to speak to voters heading to the polls.

By 7 a.m. on Tuesday morning, the state had already exceeded the 2016 voter turnout rate, with 9.8 percent. At that time, a total of 497,428 votes had been cast, most of them by mail.

Secretary of State William F. Galvin said his office expected turnout to be about 15 percent — which would be higher than turnout in the last two comparable state primaries in 2016 and 2012. (Given the COVID pandemic, 2020 was an anomaly.)

Leslie Morgan, a high school English teacher, said she came to the Friends Center to vote for Decker, as she has done in several election cycles.

She said she likes Although she appreciated Decker’s policies on gun control and environmental protections and valued MacKay’s progressive policies, she wanted a representative with multi-term experience.

“Sometimes I’m happy with what I already know,” Morgan said, adding, however, that she is unhappy with the current political calendar structure, which has primaries right after Labor Day.

“I almost forgot, but thank God I talked to a friend who reminded me,” she said. “I think that means fewer people will vote.”

Owen Andrews, 67, stood outside the Baldwin School in Cambridge holding a sign for MacKay.

He said his decision was a way to express his dissatisfaction with the State House leadership, which he said was “lacking in accountability,” and to express his enthusiasm to challenge an incumbent – a decision he rarely gets to make.

“As a Democrat, I find that unacceptable,” said Andrews, a retired poet and educator. “I don’t know what’s going on with the way the (Democratic) party runs things that nobody feels safe challenging an incumbent. That to me indicates a certain decadence, and I would like to change that. I would like there to be elections every year. Then it’s a democracy. Right now, it’s something else.”

Katharine Lange, 27, of Albert F. Argenziano School in Somerville, said she is glad to have a choice of multiple state legislators in Somerville because it shows elected officials that they can lose their seat at any time if they do not do their jobs.

Other districts do not have this luxury, she said, and that has consequences.

“The legislative session was pretty disappointing. At the end they left a lot of things on the table,” she said.

However, she ultimately decided to stay with Uyterhoeven as she had only held the post for one term.

“She seems to be as progressive as I find Somerville,” Lange said. “She’s done a good job so far.”

Globe correspondent Izzy Bryers contributed to this report.

You can reach Samantha J. Gross at [email protected]. Follow her @samantha_grossSpencer Buell can be reached at [email protected]. Follow him @SpencerBuell.