Washington ? A federal court Thursday loosened restrictions on corporations, unions and other special interest groups that run political advertising in peak election season.

The 2-1 ruling said groups may mention candidates by name in commercials as long as they are trying to influence public policy, rather than sway an election.

The ruling came in a challenge to the so-called McCain-Feingold law designed to reduce the influence of big money in political campaigns. The law banned groups from using unrestricted money to run advertisements that name candidates two months before a general election or one month before a primary.

Wisconsin Right to Life, an anti-abortion group, has been fighting the law since 2004, when it sought to run an advertisement urging voters to contact Wisconsin Sens. Russ Feingold and Herb Kohl, both Democrats, and ask them not to hold up President Bush’s judicial nominees.

Because Feingold was running for re-election in 2004, the ad was prohibited. Wisconsin Right to Life argued that it wasn’t trying to influence an election and said the law restricted its constitutional right to petition the government.

Some lawmakers have predicted such a ruling would create a loophole in the 2002 law. Advocacy groups have used ads similar to those paid for by the Wisconsin group to advocate for and against candidates.

Supporters of the law quickly criticized the ruling. Rep. Martin Meehan, D-Mass., a co-sponsor of the campaign finance law, said he was disappointed. The decision was written narrowly and should not be seen as a “carte blanche” to get around the law, Meehan said.

The case automatically heads to the Supreme Court for review. If the high court agrees with Thursday’s decision, the justices may have to establish a test to differentiate genuine issue ads from phony ones.

Federal Election Commissioner David M. Mason said the commission would review the opinion and hoped to have the matter resolved by the 2008 Iowa caucuses.