The Supreme Court has failed to decide on whether a scathing documentary about Hillary Rodham Clinton that was shown during the presidential race should be regulated as if it were a campaign ad.

The court said Monday it will hear arguments in the case again in a special session on Sept. 9. The justices said they want lawyers to address whether the court should overturn its earlier rulings on limiting corporate and union contributions in federal elections.

Citizens United, a conservative not-for-profit group, wanted to air ads for the movie in Democratic primary states and also make the film available to cable subscribers on demand without complying with federal campaign finance law.

But lower courts have said the movie looked and sounded like a long campaign ad, and therefore should be regulated like one.

At the time of "Hillary: The Movie," the New York senator was competing with Barack Obama for the Democratic presidential nomination. She is now secretary of state in the Obama administration.

The court's composition will be different by the time it rehears the case. Justice David Souter plans to retire this month, and Obama has nominated Sonia Sotomayor, a judge from the 2nd U.S. Circuit Court of Appeals, to replace him.