Susan Collins challenger Sara Gideon cruises to victory in Maine Democratic Senate primary

Collins is one of the most endangered Senate Republicans running for reelection this year

For months, Maine’s Democratic state House Speaker Sara Gideon has been running a general election-type Senate challenge against longtime GOP Sen. Susan Collins.

Now it's official that she will face off against Collins come November.

The Associated Press projected Gideon the winner of Tuesday’s Democratic Senate primary in Maine, as early unofficial vote totals showed the House Speaker was far ahead of her more progressive rivals, lobbyist Betsy Sweet and lawyer Bre Kidman.

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Gideon -- who has the backing of national Democrats and who scored eye-popping fundraising hauls -- will now concentrate 100 percent of her efforts to oust Collins, a moderate who’s considered one of the most endangered Republicans running for reelection this year.

The GOP currently holds the Senate by a 53-47 majority. But Republicans are defending 23 of the 35 seats up for grabs in November, with more than half a dozen GOP incumbents facing challenging reelections bids.

Gideon quickly took to Twitter on Tuesday night to emphasize that "We have 111 days to defeat Susan Collins, and we have to make every moment count."

Gideon will now inherit nearly $4 million in crowdfunded contributions raised for Collins’ eventual Democratic challenger. The fund was set up during the epic 2018 Senate battle over Supreme Court Justice Brett Kavanaugh’s confirmation. Collins ended up supporting the president’s controversial high court nominee.

Collins, who faced no opposition in the GOP primary, said she's looking forward to November.

"I'm looking forward to the campaign in the fall because I know that I have your support. Together we will prevail, and I can assure you that I will continue to fight hard for the state of Maine each and every day," Collins said in a video sent by Twitter.