As the Supreme Court mulls the first direct challenge to its 2010 Citizens United v. Federal Election Commission ruling, reform advocates have lobbied the court to revisit and fully debate the constitutionality of corporate political spending.

But it’s a risky strategy. If the court decides to take up and argue the challenge in question, which involves a Montana corporate spending ban, it’s anyone’s guess where it will come down.

The justices could reverse course from Citizens United and embrace new political money restrictions, as reformers argue they should. But the high court also could opt to deregulate the system further, law professor Richard Hasen said. That would leave Citizens United opponents worse off than they are today.

For example, the court might decide to throw out one of the few remaining rules on the books, such as the existing limits on contributions to parties and candidates.

“You’ve got people in the campaign finance reform community pushing for a hearing, as though that’s likely to get the court to reconsider Citizens United,” said Hasen, a professor of law and politics at the University of California-Irvine. “Not only do I think that’s a long shot — because I don’t see any evidence that the court majority has changed its position on this — I also think it could make things worse.”

None of that has stopped Members of Congress, attorneys general, activist groups and legal scholars from urging the high court to take up the Montana case, which is known as American Tradition Partnership v. Bullock. The high court signaled this week that it would meet in private conference on June 14 to decide how to proceed in the case, which turns on a constitutional challenge to a 100-year-old Montana corporate spending ban.

The Citizens United ruling, which ended decades-old limits on direct corporate and union spending, technically nullified the Montana law. But the state refused to take its corporate spending ban off the books. A trio of corporations then challenged the ban as unconstitutional, but in December the state Supreme Court sided with Montana and upheld the law.

The Supreme Court stayed that ruling in February. The high court will now decide as early as June 15-18 whether to summarily reject the state Supreme Court’s ruling, as the corporations challenging the law have requested. The court could also refuse to take up the case, leaving the Montana law in place — an outcome few expect. The court’s other option is to take up the case for full argument and briefing.

More than a dozen amicus briefs have flooded the court in the Montana case, increasing the likelihood that the justices will opt for a full rehearing, Hasen said. Those filing briefs include Sens. John McCain (R-Ariz.) and Sheldon Whitehouse (D-R.I.), who teamed up to urge the court either to let the Montana law stand or to fully revisit the corporate spending questions raised in Citizens United.

Close to two dozen attorneys general also signed on to support the amicus brief filed by Montana Attorney General Steve Bullock, thanks in part to a lobbying campaign by the progressive group Democracy for America. Sen. Mitch McConnell (R-Ky.), the U.S. Chamber of Commerce and the conservative group Citizens United, which was at the heart of the high court’s 2010 ruling, filed briefs in support of the corporations challenging the Montana ban.

Reform advocates acknowledge that if the high court opts to hear and argue the Montana case, there’s no guarantee the justices will reconsider Citizens United.

When the high court issued its stay of the state Supreme Court ruling, Justices Ruth Bader Ginsburg and Stephen Breyer issued a statement suggesting that the court should seize the opportunity to consider whether the massive political spending unleashed by Citizens United “should continue to hold sway.”

But few expect a wholesale reversal by a court that conservatives still dominate. Even if the court rejects the Montana spending ban, however, it will help activists make the public case for a constitutional amendment to reverse the Citizens United ruling, said John Bonifaz, co-founder and director of the pro-reform group Free Speech for People.

“Obviously, it’s our hope that the court does the right thing and reverses Citizens United,” Bonifaz said. “But if they don’t, it’s going to further the call for a constitutional amendment.”

If the court does take up the Montana challenge for full argument, Bonifaz predicted, the case will become a magnet for still more amicus briefs and lobbying. Reform advocates argue that the billions raised and spent by often-
undisclosed corporate interests in the 2012 elections have stirred public anger, and furnished evidence that Citizens United is not playing out as the high court anticipated.

But the ruling’s defenders argue that campaigns are more robust and competitive than ever. If anything, big spending by billionaire-backed outside groups and super PACs has fueled conservative calls for further deregulation. GOP presidential nominee Mitt Romney has argued that the solution is to lift the restrictions on direct campaign contributions, so candidates can raise and spend unlimited money.

It’s the kind of argument that Hasen, for one, warns many on the high court may find appealing.

“It’s not costless to urge the court to hear the case completely,” he warned.