Crossroads super PACs fund $4.6 million campaign ad buys

— -- American Crossroads and Crossroads GPS, two super PACs linked to former Bush advisor Karl Rove, announced plans on Wednesday to spend $4.6 million on a six state ad blitz focused on competitive Senate races.

The groups, which have largely focused on opposing President Obama's 2012 re-election campaign, are launching ads that target several of the most hotly-contested Senate races of 2012, as identified by Yahoo News.

American Crossroads is spending $2.6 million on television ads going after Democrats Bob Kerrey in Nebraska, Rep. Shelley Berkley in Nevada, and Tim Kaine in Virginia. The commercials are specific to each candidate, hitting Kerrey, a former Senator, on his record, Kaine on his ties to Obama, and Berkley on ethics.

Crossroads GPS, which is not required to disclose its donor information, is running ads in Missouri against Sen. Claire McCaskill, Heidi Heitkamp in North Dakota, and Sen. Sherrod Brown in Ohio.

"We're turning up the heat on Washington to fix the debt mess and stop President Obama's destructive health care takeover," Nate Hodson, Crossroads GPS Director of State and Regional Media Relations, said in a statement. "These ads alert citizens to where policymakers stand and equip them to advocate for the practical solutions contained in the New Majority Agenda."

The ads begin airing Wednesday in state-specific media markets and will run for two weeks.