The survey, from pollster and Republican strategist Mark Blankenship, give Tennant 40 percent support in the Democratic field, leading state Supreme Court Justice Robin Davis by 28 percentage points. Attorneys Nick Preservati and Ralph Baxter both receive only one percent support.

Capito topples Davis by 19 percent, with more than 50 percent support, while 18 percent said they were undecided.

But Capito's job approval is now at 54 percent, a decline since Blankenship's February poll of the race, when 63 percent of those polled approved of the job she's doing in Congress. Overall, 28 percent disapprove of Capito's job performance, and 17 percent still don't know enough about her to decide.

It's unclear what bloc of voters is shifting, or whether this reflects undecided voters becoming more familiar with her as she establishes her campaign. 

Sen. Joe ManchinJoe ManchinPruitt sworn in as EPA chief EPA breaks Twitter silence to congratulate new head Dem senator: I may face 2018 primary from Tea Party-esque progressives MORE's (D-W.Va.) job approval has declined seven percentage points since a March poll, possibly an indication his work stewarding a failed gun control bill through the Senate hurt him in his home state. He still maintains 63 percent job approval, however.

With no Democrat yet to announce a run for retiring Democratic Sen. Jay RockefellerJay RockefellerObama to preserve torture report in presidential papers Lobbying world Overnight Tech: Senators place holds on FCC commissioner MORE's seat, Capito has time to improve her standing among West Virginia voters. And her early start in the race — she announced last year — has given her time to establish a substantial fundraising lead.

The survey was conducted among 406 West Virginia voters from May 1-2 and has a margin of error of plus or minus 4.87 percentage points.