The U.S. Supreme Court ruled three years ago that political action committees consisting of corporations as well as labor unions and other special interests have a First Amendment right to spend freely on elections.

A flood of money followed. Information about where that money was coming from — in other words, who was trying to influence the elections — remained murky, often by design.

House Bill 1147 makes a good effort to clear things up. The Legislature should use the bill as the vehicle to require super PACs — those that make independent expenditures not coordinated with political candidates — to disclose the names of top donors when it’s most useful to voters.

Like other noncandidate committees, super PACS are required to disclose the sources of their funds, but state Attorney General David Louie noted in Legislature testimony that "regular reports are filed relatively infrequently, and after the fact." It would better serve the voting public if they were told immediately who was paying for the political ads they were watching.

Because Congress has not acted to increase disclosure, it’s up to the states to act individually. Other states have already done so. HB 1147 would require a super PAC to include the names of its three top contributors in ads purchased for television, radio, print or Internet ads. In doing so, HB 1147 would provide real-time disclosure of the names without infringing on their free speech.

The bill makes other transparency improvements as well. Under present state law, PACs must report only the receipt of late contributions just before an election, but not how the donated money was spent. The bill would require PACs to file campaign-finance reports disclosing spending and identify the causes or candidates targeted in the final days before elections.

Such requirements would have been revealing in last year’s state and county elections in Hawaii, as 16 super PACs spent $4.8 million, according to the state Campaign Spending Commission. Most of that expenditure was made in the Honolulu mayor’s race: Pacific Resource Partnership PAC, financed by union carpenters and private contractors, sought to support the city’s rail project by criticizing former Gov. Ben Cayetano, the anti-rail mayoral candidate.

The ads helped keep Cayetano from achieving a majority vote in the primary race and resulted in support of Kirk Caldwell in the November runoff without associating him with their hard-hitting negative content.

Candidates should welcome the super PAC transparency, as Jean Aoki of the League of Women Voters noted during the 2010 campaign, long before last year’s anti-Cayetano ads. "Honestly," she said, "if I were a candidate, some of the things said about the opponent would distress me."

Enactment of the bill would not suddenly cleanse future elections in Hawaii. However, it would cause major potential donors of PACS to consider whether they want to be associated publicly with negative and misleading political ads. But most important, it would introduce some much-needed openness to a political practice that has become increasingly influential.