House Majority Leader Eric Cantor (R-Va.) has released a TV ad hitting his primary opponent, college professor David Brat, a sign the high-ranking Republican is not taking his challenger lightly.

The ad casts Brat as "liberal" and seeks to tie him to Sen. Tim Kaine (D-Va.). The narrator says Brat worked on Kaine's "Council of Economic Advisors" when Kaine was governor. An anti-Brat Web site from the Cantor campaign cites a 2007 state Senate resolution designed to confirm Brat and others to Kaine's "Board of Economists."

Cantor is not viewed as vulnerable to Brat, an economics professor at Randolph-Macon College.

Brat's campaign did not immediately respond to a request for comment. He told WWBT TV in Richmond, which first spotted the ad, that Cantor "is out of control on this one" and rejected the claim he served on the "Council of Economic Advisors."