The leader of the U.S. Senate Republicans doubled down on his support for the U.S. Supreme Court ruling, Citizens United, that struck down limits on corporate spending in politics, asking the justices to throw out a ruling in a Montana case that may give the justices a shot at revisiting the controversial 2010 decision.

Senate Minority Leader Mitch McConnell filed a brief along with the U.S. Chamber of Commerce, a business lobbying group, asking the justices for an immediate reversal of a recent Montana Supreme Court decision upholding a strict ban on corporate spending on state elections.

The ruling of the Montana Supreme Court is in direct contravention of this Court's ruling in Citizens United, McConnell wrote. Nothing has occurred to warrant reconsideration of Citizens United. The First Amendment barrier to [campaign finance] legislation has not diminished. And there is no basis for concluding that any quid pro quo corruption, the only kind that this Court has found relevant, has occurred as a result of the ruling.

In January, the Montana Supreme Court rejected the foundation of the landmark 5-4 ruling in Citizens United: independent spending by corporations and unions in federal elections does not give rise to corruption or the appearance of corruption.

The Montana court said the state's unique history with Copper Kings -- wealthy 20th century mining industrialists who bribed lawmakers and judges -- justified the 100-year-old ban on direct corporate spending in politics.

That decision, now on hold, was appealed to the Supreme Court, forcing the justices to make a choice: overturn the Montana ruling without oral arguments or give the case a full review to reach a decision on the merits about whether the state is bound to apply Citizens United to its election laws.

Giving the Montana case a full review will give the [Supreme 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, Justices Ruth Bader Ginsburg and Stephen Breyer -- liberals on the losing end of the Citizens United ruling -- wrote in a February brief.

This is not to say Citizens United's influence on the U.S. political landscape may be short-lived; the court's conservative majority that struck down federal campaign finance laws is still on the bench. But reviewing the case is a chance to put the controversial ruling on corporate influence in the U.S. political system back in the spotlight.

According to SCOTUSblog, four votes are needed to review the Montana case while five are needed for a summary ruling that would overturn the state Supreme Court decision.

One group critical of Citizens United filed a brief recently urging the justices to use the Montana case as a vehicle to revisit the controversial decision.

This court has consistently recognized that in the face of a genuine danger of corruption and appearance of corruption of this magnitude, wrote a nonpartisan group called Free Speech For People, Congress and the states cannot be left powerless to act.