Maine state Sen. Emily Cain easily defeated state Sen. Troy Jackson in the Democratic primary in Maine’s 2nd district.

In the Republican primary, former state Treasurer Bruce Poliquin stymied former state Sen. Kevin Raye's third bid for the seat, giving Democrats their preferred candidate in the general.

With 66 percent of precincts reporting, Cain took 73 percent support to Jackson’s 27 percent support. Poliquin had 55 percent of the vote to Raye's 45 percent.

Jackson was a rare Democrat to draw the opposition of the League of Conservation Voters, which released a poll last week that had Cain up by 35 points. She also drew the backing of EMILY’s List and progressive group in her bid.

Poliquin's success is another win for conservatives, on a night that a Tea Party-backed challenger orchestrated a stunning upset of House Majority Leader Eric Cantor (R-Va.) in his primary. 

The former treasurer and businessman had portrayed Raye as liberal during their primary fight, and pledged to stand up for conservative values, while Raye emphasized a commitment to compromise and his experience as a former chief of staff to former Sen. Olympia Snowe (R-Maine).

While Republicans hope to make it competitive, Democrats are favored to hold the seat, which is vacant with Rep. Michael Michaud’s (D) run for governor.

—This piece was updated at 10:50.