The ad is part of the group's $8.1 million effort in 11 districts nationwide. It's one of their standard spots, attacking Vilsack for her support for President Obama's healthcare law and charging that it cuts billions from Medicare and results in a new tax on the middle class.

Vilsack has put up a strong fight to unseat King, an outspoken Tea Party-backed politician who has held office since 2003. She's lagged slightly behind King in fundraising, however, and entered the final stretch of the campaign with less than half as much cash on hand as the incumbent.

The Hill rates this race as leaning Republican, but Crossroads GPS's entry there indicates Republicans don't yet see King's win as a sure thing.

In addition to King, Crossroads GPS is launching new ads in districts it's previously engaged in, but with a more candidate-specific focus. In California's 21st District, the group targets Democrat John Hernandez for what it characterizes as his position in favor of higher taxes, and it targets Brendan Mullen in Indiana's 2nd District for being "hand-picked" by "big-government liberals."

Against Steven Horsford in Nevada's 4th District, the ad notes that he resigned from a state board after a nonprofit he directed received grants from the board. And in New York's 21st District, Crossroads GPS targets Rep. Tim BishopTimothy (Tim) Howard BishopDems separated by 29 votes in NY House primary Flint residents hire first K Street firm House moves to vote on .1T package; backup plan in place MORE for aiding a constituent and then possibly inappropriately asking for donations.

Watch the King ad: