Portland, Maine - Massachusetts Senator Elizabeth Warren appeared before a huge crowd at a massive Maine campaign rally in support of Graham Platner's insurgent Senate run.

"I'm here because Washington needs fighters, and Graham Platner is the fighter we need," Warren told the roaring crowd in Portland.

"Graham is a combat veteran. He's an oyster farmer, he's an organizer, and he's the person who is going to beat Susan Collins."

The progressive senator went on to tout Platner's ambitious agenda, and his straight-forward approach to politics, including his commitment to free universal healthcare and a fairer social welfare system.

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Platner won't "bend a knee to the big corporate donors," or to "billionaires" who refuse to pay taxes, she insisted.

"The path to the majority for Democrats in the United States Senate runs right through Maine. This is it. This is the all-hands-on-deck moment from now until November."

Warren's appearance, which was announced last week, followed her "excited" endorsement of Platner in March, where she declared that he "has the grit" to stand up to President Donald Trump.

Platner joined Warren onstage in Portland, telling the crowd that they must "dream big" if they want to beat their opponents.

"We need to be willing to understand that we’re all being exploited by the exact same people," he said. "It's not immigrants, it is not trans kids, it's billionaires."

Recent polls give Platner a 33% lead over his Democratic opponent, current Maine Governor Janet Mills, and far ahead of incumbent GOP Senator Susan Collins, who has held the seat since 1997.