PORTLAND, Maine (AP) — Maine Democrat Graham Platner has picked up another high-profile endorsement in his bid to flip a key Senate seat blue, marking another sign of the oyster farmer and combat veteran’s political resiliency even as he continues to face controversy throughout his campaign.

Arizona Democrat Ruben Gallego announced Monday that he was backing Platner, saying that the first-time candidate “reflects the grit and independence that defines Maine.”

“Graham Platner is the kind of fighter Maine hasn’t seen in a long time, someone who tells you exactly what he thinks, doesn’t owe anything to the special interests, and wakes up every day thinking about working families,” said Gallego, who won a Senate seat in Arizona in 2024 by more than 2 points while Trump carried the state by nearly 6 points.

Platner has previously been endorsed by Vermont Sen. Bernie Sanders, an independent who caucuses with Democrats, and New Mexico Sen. Martin Heinrich, a Democrat.

However, Senate Minority Leader Chuck Schumer has endorsed Platner’s main opponent, Maine Gov. Janet Mills.

Both Platner, 41, and Mills, 78, are hoping to unseat Republican Sen. Susan Collins, 73, a five-term incumbent who announced last month that she was running for another term. A victory in Maine is crucial for Democrats’ efforts to take back control of the Senate. The Democratic Party needs to net four seats to retake the Senate majority, and they are aiming to do that in Maine, North Carolina, Alaska and Ohio.

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Platner has gained traction with his anti-establishment image and economic equality message. He’s pressed forward despite controversies over old social media posts and a tattoo resembling a Nazi symbol, which he recently had covered up.

Gallego is among the Democrats named as possible 2028 presidential contenders. Last fall, he stumped in New Jersey, Virginia and Florida, where he campaigned for Democrats who went on to win their elections.

“I have an immense amount of respect for him and I’m looking forward to joining him as a fellow Marine and combat infantryman in the U.S. Senate,” Platner said in a statement.

Kruesi reported from Providence, Rhode Island.