wITHIN THE contentious arena of campaign finance reform, one of the few areas in which all sides agree — or claim they do — is on the importance of disclosure. For years, opponents of other campaign finance reform measures argued that they were unneeded because disclosing the donations would cure other asserted ills, such as corporate donations or unlimited checks.

Until recently, that is. Two years ago, Congress narrowly failed to pass legislation that would have required disclosure of the gusher of secret money flowing into elections by way of nonprofit groups and trade associations. The measure, known as the DISCLOSE Act, passed the House, then under Democratic control, but failed to garner enough votes in the Senate. Now, with the money spigot flowing with full force in the Republican primary, backers of the DISCLOSE Act are trying again, with a measure narrowly focused on disclosure and updated to take account of the new phenomenon of super political action committees.

The explosion of super PACs has obscured the even more disturbing involvement by tax-exempt groups that run barely disguised campaign ads but, under current rules, never have to reveal the identities of their donors. The measure, sponsored by Rep. Chris Van Hollen (D-Md.), would require such disclosure without infringing on the groups’ non-campaign activities. Organizations that want to keep the identity of non-campaign donors private can set up separate funds to handle election-related spending.

Corporations, unions, other outside groups, and super PACs would have to report, to the Federal Election Commission, within 24 hours of making a $10,000 campaign expenditure or financial transfer to other groups, which can then be used for campaign-related activity. In addition, top donors would have to be disclosed in television and radio ads, and leaders of corporations, unions and other outside groups would have to make “stand by their ads” declarations.

The legislation would address the gap in the disclosure schedule covering super PACs. These entities are required to report their donations, but the timetable allows them to avoid reporting their activity until after the conclusion of key primaries. If these entities are an unfortunate new fact of political life, at least voters ought to know who is bankrolling them before voting.

As the Supreme Court explained in its Citizens United ruling, “disclosure permits citizens and shareholders to react to the speech of corporate entities in a proper way. This transparency enables the electorate to make informed decisions and give proper weight to different speakers and messages.” What, exactly, is the problem with transparency?