Unfortunately, there appears to be little likelihood that the Supreme Court will reconsider its landmark ruling two years ago that has allowed corporations to dump obscene amounts of cash into political campaigns without revealing their activity.

Hopes that the court might come to its senses were dashed two weeks ago when it overruled a Montana Supreme Court ruling upholding that state's 1912 law banning corporate political donations. Montana Gov. Brian Schweitzer is calling for a federal constitutional amendment prohibiting corporate donations. But that uphill battle is unlikely to succeed with such a partisan Congress.

At the least, lawmakers should require more disclosure, so voters can know which corporations are spending what on candidates.

Corporations are giving relatively small amounts to the super PACs, which must disclose their donors. They prefer to send cash to tax-exempt organizations that aren't subject to the same disclosure rules that PACs, parties, and candidates must follow.

Many of the groups receiving corporate political cash have been given tax-exempt status under section 501(c)4 of the federal tax code because they supposedly promote "social welfare." They deny being politically oriented by buying "educational" advertisements, which serve conveniently to undermine the politicians they dislike.

A number of the super PACs have sister 501(c)4s that they use to funnel the bottomless pits of cash contributed by undisclosed corporate donors. Karl Rove's American Crossroads has Crossroads GPS, while the pro-Obama Priorities USA Action has Priorities USA. According to the New York Times, such tax-exempt groups outspent super PACs by a 3-2 margin in the last election.

All this dark money from secret contributors both compounds and facilitates the political influence of corporations. They are more at ease these days because they can spend however much they want anonymously and not have to answer for their political expenditures.

The disclosure loophole opened by the court's Citizens United ruling shrouds political campaigns in layers of secrecy. The public doesn't get to know who is really funding political ads. Groups such as the Center for Political Accountability can only track corporate contributions that have been voluntarily disclosed.

The impact of the Citizens United ruling was made worse by its not requiring more transparency. Yet the 5-4 majority ruling in that case was implicitly built on the assumption that corporations should disclose their political contributions.

Justice Antonin Scalia said in his opinion that protecting corporate free speech would open up the marketplace of political ideas. But that only works when the public has the information it needs to evaluate the different political messages it is receiving.

"Disclosure is the less-restrictive alternative to more comprehensive speech regulations," Scalia wrote. If that is so, then unlimited money should not be allowed to flow into political campaigns without also setting proper disclosure requirements. Congress must find a way to fix that.