Maine House Speaker Sara Gideon won Tuesday’s Democratic primary for U.S. Senate, setting the stage for a contentious and high-profile contest against Republican Sen. Susan Collins this fall.

House Speaker Sara Gideon says hello to some of her supporters near the Woodfords Club in Portland on  Tuesday Brianna Soukup/Staff Photographer)

The Associated Press declared Gideon the winner over Democratic opponents Betsy Sweet and Bre Kidman just after 9:30 p.m. With 13 percent of precincts reporting, Gideon had received 70 percent of the vote followed by Sweet with 21.8 percent and Kidman with 3.2 percent.

Polls closed at 8 p.m. but full results could take longer than typical to compile because so many people — more than 200,000 voters — had requested absentee ballots rather than vote in-person at the polls amid the coronavirus pandemic. But Gideon’s massive margin means she will likely avoid a ranked-choice tabulation against Sweet and Kidman.

The Democratic race to take on Collins pitted Maine’s House Speaker — the favorite among national party leaders — against two more progressive candidates who said their election would help usher in much-needed changes to the Democratic establishment in Washington.

Earlier Tuesday, the three candidates visited polling places from Presque Isle to Portland and from Bar Harbor to Biddeford on an election day unlike any other in recent history. Giden will now take on a well-known, well-funded incumbent in a race that is already drawing national attention and money because of its implications for which party controls the U.S. Senate.

Gideon campaigned on such bedrock Democratic issues as reproductive rights, expanding access to affordable health care, the environment, LGBTQ concerns and education. A mother of three who served on the Freeport Town Council, Gideon has represented the town for four terms in the Maine House, including the last 3½ years as House Speaker.

Gideon also proudly points to her numerous, high-profile clashes with former Republican Gov. Paul LePage as evidence of her political toughness and willingness to stand up for Democratic values.

Sweet has been a well-known figure inside the Maine State House for decades as she advocates on behalf of low-income Mainers, women, sexual assault survivors, the disabled community and other underrepresented groups. The Hallowell resident said those decades of lobbying — including during the budget-writing process — demonstrate her life-long commitment to progressive issues and provide her with valuable knowledge of the political process.

Sweet ran for governor in 2018 and finished third in the seven-person Democratic primary after picking up significant support during the ranked-choice tabulation of the results.

Both Sweet and Kidman campaigned on the need for Congress to enact Medicare for All, a Green New Deal and to work to lessen the influence money on politics.

Betsy Sweet talks to supporter Joan Kraus outside the polling center at South Portland Community Center on Tuesday.  Ben McCanna/Staff Photographer

An attorney who often serves as court-appointed defense counsel to low-income clients, Kidman spent nearly all of the roughly $23,000 raised the campaign on charitable programs, including helping families during the COVID-19 pandemic. Kidman, who self-identifies as non-binary and goes by the pronouns they/them/their, said their background as a medium-income resident would help them represent the interests of average Maine households.

But Sweet and Kidman were overshadowed by Gideon as soon as she entered the race and picked up endorsements from big-money, influential national groups such as EMILY’s List and Planned Parenthood Action Fund. Critically, Gideon also immediately landed an endorsement from Senate Majority Leader Chuck Schumer, D-New York, and the support of the national party’s massive campaign machine, the Democratic Senatorial Campaign Committee.

Those high-profile endorsements helped Gideon raise more than $23 million for her campaign as of June 24, demolishing all previous fundraising records in Maine even before the Democratic primary. Since announcing her candidacy in June 2019, Gideon has focused almost exclusively on Collins, not her primary opponents.

Factoring in the nearly $17 million raised by Collins’ campaign to date and the tens of millions in spending by outside groups, Maine’s Senate race is already the most expensive race in state history and could be one of the costliest Senate races nationwide in 2020.

Collins is facing the toughest reelection fight of her more than two-decade-long career in Congress as Democrats seek to shatter her reputation as a moderate yet influential Republican vote in an increasingly conservative caucus.

Instead, Democrats portray Collins as toeing the party line in the era of Donald Trump — who polls suggest is deeply unpopular among the majority of Mainers — or only voting against Senate Majority Leader Mitch McConnell, R-Kentucky, when it doesn’t matter or when she is part of a broader revolt.

All three Democrats in the race cited Collins’ pivotal vote in October 2018 to confirm Supreme Court Justice Brett Kavanaugh as a key reason for their decision to enter the race. Collins’ high-profile decision on Kavanaugh, who was facing allegations of sexual assault from his high school days, also sparked an unprecedented fundraising campaign.

Using internet-based crowdfunding to raise small-dollar donations, Be a Hero PAC, Mainers for Accountable Leadership and the Maine People’s Alliance raised more than $4.1 million for whoever won the Democratic primary to challenge Collins.

“In 2018, after (Collins) voted for Kavanaugh, Mainers raised $4 million for her future opponent,” Ady Barkan, the progressive activist who co-founded the national Be A Hero PAC, said Monday in a Twitter post. “Now, they’re days away from handing that check over. Are you ready? The fight to unseat Susan Collins is about to heat up.”

Bre Kidman, a criminal attorney and performance artist. Derek Davis/Staff Photographer

Voter turnout at the polls was relatively light on Tuesday but is likely to be offset by the more than 200,000 absentee ballots requested by Mainers, which is a record for a primary.

Kathleen Marra, chairwoman of the Maine Democratic Party, thanked election administrators for staging Tuesday’s election during the coronavirus pandemic.

“I also want to thank each candidate who competed in today’s primary election on their hard fought campaigns, especially under challenging circumstances,” Marra said in a statement. “As we await final results, it’s clear that Maine people are fed up with Republicans in Washington and fired up by Democrats who wake up every day and fight for them. I look forward to working with our strong slate of candidates to continue making progress on issues that matter most to Mainers.”

Several Democratic voters mentioned Gideon as they cast their ballots in-person on Tuesday despite the coronavirus pandemic.

Auburn voter Jen August said she wanted to cast her vote for Gideon.

“Voting I think is worth the risk,” August said.

Likewise, Paul Beland of Lewiston said he had contemplated voting absentee but was working from home and had time to vote in person, so he did.

“I felt it was my duty to vote,” Beland said. “A couple of the local bond issues were a big thing for me too, and I’m pretty strongly in favor of Sara Gideon and wanted to vote for her.”