Democrats have been fighting a candidate curse in the Montana Senate race, and they're losing.

First, in July of last year, former Montana Gov. Brian Schweitzer decided to forego a bid for Senate, shocking many Democrats and paving the way for Lt. Gov. John Walsh to run.

But, on Thursday, Walsh quit his bid for Senate too, having flailed for two weeks after the New York Times uncovered multiple serious instances of plagiarism in an academic thesis.

Now, Democrats will need to find a third suitable Senate candidate before Aug. 20 — but the climb is steeper than ever.

The candidate will need to launch a campaign with only three months until Election Day, for a Senate seat most Democrats have given up on winning. "I think it's accepted as a lost cause at this point," said one Democratic strategist with ties to Montana.

These Democrats have said they won't run, but at least some people in their party are floating the idea in one last effort to keep the Senate seat in play:

Brian Schweitzer

For a brief moment Thursday, there seemed to be a glimmer of hope that Schweitzer might run when one Schweitzer ally, Montana political strategist Bob Brigham, tweeted: "Today's a good day for everyone to follow @brianschweitzer. Follow him all the way to victory in November!" But, not long after, Schweitzer took to Twitter to clarify. "I respectfully decline to seek the Senate nomination," Schweitzer said. "Many thanks to John Walsh & I'll support whoever the next nominee turns out to be."

A bid by Schweitzer would have no doubt been complicated by some inflammatory remarks he made recently, such as that former House Majority Leader Eric Cantor sets off Schweitzer's "gaydar." And Republicans have boasted about potentially damaging opposition research against Schweitzer, which might have led him to decide against running in the first place.

Nancy Keenan

The former president of the National Abortion Rights Action League-Pro-Choice America (NARAL Pro-Choice America) returned to Montana this year after a 13-year hiatus in Washington, D.C., to work for the political firm Hilltop Public Solutions. Her work has included advising Walsh's campaign; now, some Democrats see her as a logical successor to him, although Keenan has not indicated publicly whether she would be interested in taking up Walsh's mantle.

Stephanie Schriock

Schriock, president of the major pro-Democratic group EMILY's List, is a Montana native who was heralded as a top potential recruit for the Senate seat — until she said thanks but no thanks. "I would love to say yes, but this is not the right time," Schriock said in July 2013. If the time wasn't right then, it likely won't be now.

Carol Williams

Although she does not have the national profile of some other potential Senate candidates, Williams is well-known in Montana politics as the first woman to serve as majority leader in the Montana state Senate. Since leaving the statehouse in 2012, Williams has taken up the cause of electing more women to office, and she is on the board of Carol's List, a group — named for her, in the vein of EMILY's List — established for that purpose.

Last year, Williams said she was approached to run for Senate or for Montana's House seat but opted out. “I didn’t really think a lot about it,” she said at the time, as reported in the Missoulian. “I was flattered that they thought about me. I’m doing what I really want to do — raise money and help elect Montana women to the legislature.”

Adding to her potential appeal, Williams is part of a well-known political family: She is married to former Rep. Pat Williams, who also fielded calls to run for Senate, and also declined.