U.S. Senate candidate Elizabeth Warren was already struggling in her bid to unseat Republican incumbent Scott Brown when her candidacy was rocked this week by revelations that seriously threaten her credibility with Bay State voters.

If Warren, a Democrat, fails to recapture the seat once held by liberal icon Ted Kennedy, it will reverberate far beyond Massachusetts, making it far more difficult for her party to maintain control of a Senate in which it has just a four-seat majority.

"If Democrats cannot beat Brown, it's hard to see how they keep their majority," Jennifer Duffy, a senior editor for the Cook Political Report, told The Washington Examiner.

Warren's once-rosy election prospects have bee seriously diminished by a series of gaffes and missteps, the most recent headline-grabbing incident erupting Tuesday when it was reported that the Harvard University law professor claimed to be a minority because she's part Cherokee.

It turns out Warren has a tiny fraction of Native American blood, according to a genealogist, but being 1/32nd Cherokee is probably not enough to identify herself as a minority to the Association of American Law Schools, where she is listed as a minority professor from 1986 to 1995. In 1996, the Harvard Crimson, a student newspaper, identified Warren as Native American in a story about campus efforts to improve the ethnic diversity of the faculty.

Polls show Warren and Brown running even in a race Democrats had been hoping would be a relatively easy victory. This isn't the first time Brown benefited from his Democratic opponent's self-inflicted wounds. He won his seat in a special election in 2010 following Kennedy's death, in part, because of his missteps by heavily favored Attorney General Martha Coakley.

The Massachusetts Senate seat is one of three that Democrats were hoping to capture from Republicans. And its prospects in the other two, Nevada and Maine, aren't looking any better.

"They need to win at least two of these races if they want to keep their majority," Duffy said.

The Harvard Crimson story reporting that Warren was Native American was first resurrected by the Boston Herald, where a columnist on Tuesday accused Warren of "poached diversity" and predicted it would not be long before "wise guys in feathered headdresses" show up at her campaign events.

Republicans are taking Warren's claim more seriously, demanding to know whether Warren used her minority status to win jobs at various colleges, including Harvard. Such an accusation is particularly damaging because Warren's campaign has been based on her reputation for honesty and as a champion of the less fortunate who took on big corporations and Wall Street.

In addition to the story about Warren's minority claims, the Boston Globe reported that Warren had a lucrative consulting job with Travelers Insurance in which she helped the company stop asbestos-related lawsuits, work that conflicts with her image as a consumer protection advocate who was once tapped to head the federal government's newly created Consumer Protection Agency.

"I think the Native American story will pass," University of Massachusetts political science professor Maurice Cunningham said. "But it's a little hard to make the case you are purely for the consumer when you are working for Travelers Insurance."