After absorbing millions of dollars in outside spending from groups connected to the Koch brothers, congressional Democrats have made the conservative billionaires the star villains in a messaging counteroffensive. But a new nonpartisan poll highlights a problem with the plan: A majority of likely 2014 voters have never even heard of the Kochs.

A 52 percent majority of respondents in the new George Washington University Battleground Poll said they had never heard of the Koch brothers, with an additional 11 percent saying they had no opinion of the conservative industrialists. Of the small slice who registered an opinion of the Kochs, 12 percent viewed them favorably and 25 percent viewed them unfavorably. The survey is one of the first to test opinions about the Kochs since they became a big subject of political conversation in the last few years.

From Senate Majority Leader Harry Reid’s floor speeches to his party’s fundraising emails to recent TV ads from Democratic candidates and outside groups, Democrats have homed in on the Kochs recently. Americans for Prosperity, one of the groups affiliated with the Kochs, has spent around $30 million on TV ads against Democratic House and Senate candidates ahead of the 2014 elections.

Several recent Democratic TV ads responded directly to the Kochs. Democratic Sen. Mark Begich’s first TV adin Alaska blamed “the billionaire Koch brothers” for a series of false attacks against him and for shutting down an Alaska refinery, while a new ad from the Senate Majority PAC in Colorado connected GOP Rep. Cory Gardner to “insurance companies and out-of-state billionaires” funding attack ads against Sen. Mark Udall because Gardner’s policies, the narrator said, would be better for insurance companies.