Labor unions recruited Graham Platner for his U.S. Senate bid, and quickly backed the Democrat when he launched his campaign last August.

Senate Minority Leader Chuck Schumer and other national Democrats made similar moves to get Gov. Janet Mills in the race by October.

So it is not too surprising that leaders from the influential United Auto Workers and International Brotherhood of Electrical Workers have contacted Schumer and his party’s Senate campaign arm to tell them to stop backing Mills over Platner ahead of the primary that will decide who faces U.S. Sen. Susan Collins, R-Maine, in November.

The more notable part of the February pleas was the urgent tone from labor leaders who went so far as to tell the national Democratic officials that the Maine race is an example of their “failure” to consider working-class voters around the country ahead of the 2026 midterms. Continuing to back Mills could weaken Platner’s chances to unseat Collins, who is seeking reelection to a sixth term this fall and whose seat in a blue state is viewed by both parties as a must-win.

A leader of the International Brotherhood of Electrical Workers’ Second District, which includes Maine, sent a letter Monday to Democratic Senatorial Campaign Committee leadership to express “deep concern” over the national campaign arm’s involvement in the Maine primary. The Press Herald obtained the letter, which was written by Michael Monahan, the international vice president of the IBEW’s Second District, and sent to U.S. Sen. Kirsten Gillibrand, D-New York, who chairs the DSCC, along with other leaders of the campaign committee.

Mills has repeatedly been “at odds with working families” over her two terms as governor, Monahan wrote, while Platner is “the only candidate in this race who stands with working people, respects organized labor and has earned labor’s trust.” Continuing to support Mills is “not only unwise” but also “risks weakening the eventual Democratic nominee” in November, he said.

“We strongly urge the DSCC to refrain from intervening further in this primary,” Monahan wrote in his two-page letter.

United Auto Workers President Shawn Fain, whose union is endorsing Platner, reportedly called Schumer earlier in February to discuss the Maine race, and to describe what he views as “shortcomings” in the Democrats’ approach to this year’s midterms. Fain cited Maine when telling Schumer about the party’s “failure to adequately listen to working-class voters.”

NBC News first reported the details of the call Thursday night, citing two unnamed people familiar with the conversation. UAW officials and Fain did not respond Friday to the Press Herald’s request for comment. Spokespeople for the DSCC and Schumer also did not immediately respond to requests for comment Friday.

A regional leader with the International Association of Machinists and Aerospace Workers told NBC News he has scheduled a Zoom call with DSCC leaders next week to discuss the Maine race, saying his members are upset over the Democratic campaign arm supporting Mills. An official with the machinists and aerospace workers union, which has nearly 700,000 members across North America, did not immediately share more details Friday.

Reports of the calls and letters came the same week the University of New Hampshire released a poll of the Maine primary that showed Platner, a 41-year-old Sullivan oyster farmer and military veteran, with a massive lead over Mills, a 78-year-old former attorney general and prosecutor from Farmington. The same survey also had Platner up 11 percentage points on Collins, a 73-year-old Caribou native who chairs the Senate Appropriations Committee, in a hypothetical November matchup.

As outside groups backing the three candidates have started pouring more money into the race, Platner outpaced both Mills and Collins by raising $4.6 million in the last quarter of 2025.

Mills and state employees in Maine have butted heads over pay and other labor matters since she first won election to the Blaine House in 2018. In a November complaint, the union for state workers accused the Mills administration of “bad-faith” bargaining. She has also vetoed bills backed by labor groups.

But Mills and her team have pointed to state worker pay bumps under her watch, her support of a new paid leave law and the Maine AFL-CIO’s endorsement of her 2022 reelection bid, among other things, as evidence that she supports workers.

Tommy Garcia, a Mills campaign spokesperson, said the governor’s “record of fighting for workers’ rights, dignity, and pay has earned her praise from many unions throughout the state of Maine.” Maine voters “know she will continue to deliver for them,” Garcia added.

The NBC News piece came out late Thursday, hours after various outlets reported on how Platner’s campaign account had shared an antiwar social media post from a far-right figure who has promoted antisemitic and white nationalist views online. Platner’s team later deleted the post.

Platner also came under intense scrutiny after Mills entered the race when past online comments he made regarding rape, Black people’s tipping habits and rural white Americans — among other topics — came to light. He also took heat for having a Nazi-linked tattoo; Platner got the tattoo covered up in October, and he has said he didn’t know it resembled a Nazi symbol. (In a Thursday podcast interview, Platner said in regard to the tattoo that he was “not going to apologize for something that, like, I didn’t know about.”)

Still, Platner has weathered the controversies and maintained his polling and fundraising momentum. His campaign declined to comment Friday.