Washington (CNN) -- Money in presidential and congressional campaigns has already reached record heights so far this election year, thanks in part to recent rulings by the Supreme Court and other federal judges that loosened long-standing restrictions on outside corporate spending.
But now the justices are poised to revisit one of the most controversial decisions in recent years, one that gave corporations expanded "free speech" power in independent federal election expenditures.
The issue now is whether that 2010 ruling applies to similar existing state restrictions on political money from outside groups.
The justices met privately Thursday to decide whether to review a mandate from Montana's highest court. If they do, oral arguments would be held in the fall, perhaps around Election Day, though a ruling would not come until perhaps months later.
An announcement from the high court on whether the justices have accepted the petition could come Monday.
The U.S. Supreme Court in February blocked enforcement of the state ruling, which upheld Montana's century-old restrictions on independent campaign expenditures.
Opponents of the state restrictions say they conflict with the Supreme Court's landmark free speech ruling in 2010. The so-called Citizens United decision blessed unlimited campaign spending by corporations, putting them on the same free speech footing as wealthy individuals, who have long enjoyed the ability to spend freely on behalf of federal candidates.
That decision and a subsequent one from a federal appeals court in Washington have led to a proliferation of so-called super PACs -- political action committees that can raise and spend unlimited amounts of cash from businesses, unions, and advocacy groups. Limits on direct contributions to candidates by corporations and individuals remain in place.
Critics of the court-ordered sea change in campaign spending say it has created a system of "haves" and "have nots"-- tightly regulated small donors competing against lightly regulated well-heeled wealthy individuals and corporations, all seeking a voice in the crowded political debate.
The Montana justices, in their late December ruling, concluded that "unlike Citizens United, this case concerns Montana law, Montana elections and it arises from Montana history."
A coalition of organizations opposing regulation had asked the high court for "summary reversal," essentially to overturn that state ruling without the hearing oral arguments, or reading "merit briefs," in which the issue would be fully explained.
But the justices are expected to fully debate the constitutional questions, a sign some on the high court want a serious re-examination of the Citizens United ruling of 18 months ago.
Justice Ruth Bader Ginsburg had made that point in February, when the high court put the Montana ruling on hold.
"Montana's experience, and experience elsewhere since this court's decision in Citizens United v. Federal Election Commission, make it exceedingly difficult to maintain that independent expenditures by corporations 'do not give rise to corruption or the appearance of corruption,'" she said, quoting the majority opinion in the 2010 case. Fully hearing the Montana petition, she said, "will give the court an opportunity to consider whether, in light of the huge sums currently deployed to buy candidates' allegiance, Citizens United should continue to hold sway."
Justice Stephen Breyer supported Ginsburg then, and presumably both voted to accept this latest appeal for review. It takes four justices to agree to hear a case.
In Citizens United, the conservative high court majority eased long-standing restrictions on "independent spending" by corporations in federal political campaigns. It gave big business, unions and non-profits more power to spend freely in federal elections, negating to a large extent a century of government efforts to regulate the power of corporations to bankroll American politics.
The landmark ruling held there was no distinction between an individual and a corporation with respect to political speech.
"When government seeks to use its full power, including the criminal law, to command where a person may get his or her information or what distrusted source he or she may not hear, it uses censorship to control thought. The First Amendment confirms the freedom to think for ourselves," said Justice Antony Kennedy. "The appearance of influence or access will not cause the electorate to lose faith in our democracy."
Now-retired Justice John Paul Stevens has been especially vocal criticizing the conservative majority's Citizens United decision. In a recent speech, the 92-year-old Stevens said the decision has led to confusion and inconsistency in similar appeals.
He was the author of the court's dissent in the 2010 case, just months before he stepped down from the bench.
Most appeals accepted for review are fully argued and briefed, with a detailed written opinion identifying which of the nine justices either support or oppose the majority.
But nine times this term, the court has issued "per curium" opinions, which do not identify the author and are typically shorter and less detailed than typical rulings. Such appeals did not have arguments or traditional, longer deliberations.
The case is American Tradition Partnership Inc. v. Bullock (11-1179).