Opponents of a new state disclosure law on corporate political giving won a do-over Wednesday.

The U.S. Eighth Circuit Court of Appeals on Wednesday vacated an earlier ruling by a three-judge panel affirming that Minnesota can require corporations to disclose when they make such "independent expenditures." Instead, the Court of Appeals agreed to have the full court hear the case on Sept. 21 in St. Louis.

The ruling not only keeps the question alive about whether corporations can give -- unfettered -- to support a candidate, said an attorney representing Minnesota business interests. It means Minnesota's law barring direct corporate contributions to candidates could be in jeopardy as well.

"It's one of the claims we made, that corporations can donate to candidates directly," said James Bopp Jr., who represents Minnesota Citizens Concerned for Life (MCCL), the Taxpayers League of Minnesota and Coastal Travel Enterprises. The organizations argue that Minnesota's law hampers their right to free speech by improperly limiting corporate support for candidates and causes.

But State Rep. Ryan Winkler, DFL-Golden Valley, who authored Minnesota's disclosure law, said he doubts the full Eighth Circuit will go against what the U.S. Supreme Court already has established -- requiring disclosure of what a corporation paid to support or defeat a candidate is constitutional.

"If anything, they are going to listen [as a group] and make a stronger opinion than the 2-1 decision," he said.

By a 2-1 vote in May, a three-judge panel of the Eighth Circuit sided with a Minnesota federal judge who refused to block a state campaign finance law requiring corporate disclosure, allowing the law to remain in effect.

At the heart of the dispute is a 2010 state law requiring reports on corporate spending for or against candidates. The law requires two reports to be filed before the primary and two more before the general election. The law also applies to groups supported by unions.

The U.S. Supreme Court ruled last year that bans on "independent" expenditures were an infringement on free speech. But the court also said states could require disclosure of such spending. As a result, the Legislature amended the law to require disclosure.

A Minnesota corporation may donate its own money to an existing independent expenditure committee or fund without providing any information beyond its name and address. If the business solicits and receives contributions beyond its general treasury revenue, it must disclose the source of the contributions.

Bopp said he thinks the decision by the full court to hear the case means "there is a substantial question among the judges whether the original decision was correct."

It also may mean, he said, that the court will decide whether Minnesota law can prohibit corporate giving directly to candidates. Bopp said the three-judge panel did not rule on that question in May.

Winkler, however, disagreed. "I think Mr. Bopp is off base."

James Walsh • 612-673-7428