An environmental advocacy group is purchasing more airtime for a graphic TV spot that attacks Gov. Sarah Palin for her support of aerial wolf hunting in Alaska.

Defenders of Wildlife Action Fund began airing the minute-long ad "Brutal" in Ohio and Florida on Sept. 12, later expanding it into Michigan. The spot seems to have hit a nerve with animal rights activists, who have donated more than $1 million to the group since it started airing. Flush with cash, the D.C.-based action fund will soon begin running the ad in Colorado, Wisconsin, Virginia and Missouri, the site of Thursday’s vice presidential debate.

The ad also resonated with a focus group conducted two weeks ago by HCD Research and the Muhlenberg College Institute of Public Opinion. The ad “seemed to strike a chord with voters,” said Glenn Kessler, president and CEO of HCD Research, in a Sept. 15 press release. “The recent ads from both parties have had little impact,” Kessler said. “This is the first ad in over a month that seems to have broken through.”

Defenders of Wildlife Action Fund could not be reached for comment.