Republican PACs take to the airwaves Jerry Pyenson of Hackensack, NJ, right, a member of the Lyndon LaRouche political action committee, dresses as the Grim Reaper sitting near a sign put up by the LaRouche PAC outside of the American International Group headquarters on September 17, 2008 in New York City. The LaRouche campaign objects to the government's $85 billion bailed out the insurance company. WASHINGTON, April 21 (UPI) -- Officials at Republican super PACs and other outside organizations say they will concentrate on radio and TV ads attacking U.S. President Barack Obama. In Ohio, for example, the airwaves this month are already crackling with negative advertising funded by Crossroads GPS, The Washington Post reported. Crossroads GPS is affiliated with American Crossroads, founded by Karl Rove, one of President George W. Bush's top advisers. On the Democratic side, labor unions are sticking to what they see as their big strength, appealing to voters through canvassing and other work on the ground, while environmental groups are using a mix of commercials and ground work, the Post said. But Republicans believe the ground game is better carried out by party organizations. "A lot of us don't think it's efficient for outside groups to do ground-game activities," a super PAC official told the Post, speaking on condition his name would not be used. The campaign finance laws are set up to allow the parties to do that, and we believe they do it quite well. Our added value will be on the airwaves. The Supreme Court's Citizens United decision opened the floodgates for fundraising by outside groups, and experts say as much as $1 billion could be raised and spent this year.