The justices said new argument should address two key Supreme Court precedents upholding federal election law and whether the high court should "overrule either or both."
At stake in the case is a provision of a 2002 federal campaign law that bans "election communications" funded by corporations or unions close to an election.
The justices heard argument earlier this term, with former U.S. Solicitor General Ted Olson representing the producers of "Hillary, the Movie." The film's backers wanted to make it available as an "on demand" movie on cable television during the 2008 race for the presidency.
But federal courts ruled the movie, financed partly with funds from unnamed corporations, violated the 2002 McCain-Feingold law.
Deputy U.S. Solicitor General Malcolm Stewart, defending the law, suggested the Constitution not only allows the restriction of the "documentary" message when offered "on demand," but also on the Internet, on a DVD or in a book, even at a public library.
(Citizens United vs. Federal Election Commission, No. 08-205.)