Tennant was endorsed by EMILY's List for her secretary of State race, so their endorsement in the West Virginia race comes as no surprise.

In an email to EMILY's List supporters, Stephanie Schriock, who heads the organization, urges them to vote and warns that Republicans could take "this longtime Democratic seat and [turn] it red."

"I wanted to personally let you know that today we're endorsing Natalie Tennant for the U.S. Senate race in West Virginia. And if Democrats are going to keep hold of the U.S. Senate, this is a race that we have to win," Schriock writes in the email.

She also notes that electing Tennant could make history in West Virginia, as the state has never had a female senator.

Schriock makes no mention of the fact that it's likely the state will be sending a woman to the Senate no matter what party prevails — the likeliest Republican candidate, Rep. Shelley Moore CapitoShelley Moore CapitoGOP govs: ObamaCare repeal bill shifts 'significant' costs to states Here's how Congress can get people to live healthy lifestyles Overnight Tech: DOJ charges Russians with Yahoo hack | Trump to grade agencies on cybersecurity | Senators push for broadband study MORE (R), would also hold the first-female-senator distinction.

The race favors the Republican, as West Virginia went heavily for Mitt Romney in the 2012 election, but West Virginia hasn't sent a Republican to the Senate since the 1950s, and Tennant gives Democrats their best remaining shot at holding onto Sen. Jay RockefellerJay RockefellerObama to preserve torture report in presidential papers Lobbying world Overnight Tech: Senators place holds on FCC commissioner MORE's (D-W.Va.) seat after he retires.