Given a chance to make politics a little less opaque, California legislators blew it.

That's the charitable interpretation, anyway.

We'd hate to believe that they don't want voters to know who is paying for the TV commercials and mailers that dominate campaigns for candidates and initiatives, especially when witnessing the flood of money in this year's presidential campaigns.

Yet legislation requiring both candidates and political action committees to level with voters fell two votes short in the Assembly, with two members not voting, as a deadline passed on Jan. 31.

Fortunately, supporters of the California Disclose Act haven't given up.

Assemblywoman Julia Brownley, D-Santa Monica, re-introduced the bill last week. This time, her colleagues should send it on to the state Senate.

Brownley proposes three straightforward rules to help voters assess political ads:

&#149 In radio, television and Internet ads, candidates must identify themselves and affirm that they approved the message. This rule already applies to presidential and congressional candidates.

&#149 Political action committees, which frequently hide behind amorphous names such as Citizens for a Better Tomorrow or Californians for Better Government, must identify their three largest contributors of more than $10,000.

Moreover, the committee would be required to maintain a website that identifies its top five contributors of more than $10,000 and includes a link to the secretary of state's website, where all campaign fundraising reports can be reviewed.

&#149 On slate mailers, there must be an asterisk next to the name of any candidate for whom a payment was made — either by the candidate or an independent committee. Existing law requires an asterisk only if the candidate paid for a spot on a slate card.

Brownley's bill sailed through two committees. On the Assembly floor, the bill got 52 votes, falling two short of the two-thirds majority needed for approval. Republicans Jeff Gorrell of Westlake Village and David G. Valadao of Hanford didn't vote.

Opponents, all but one a Republican, argued that disclosure is antithetical to free speech. Nonsense. Disclosure is a foundation of campaign finance laws and a bulwark against corruption.

Almost $200 million was spent on initiative campaigns alone in 2010, with hundreds of millions more spent by candidates for statewide office and the Legislature as well as independent expenditure committees, the state equivalent of the super PACs dominating this year's presidential campaign.

A recent California Poll found that 84 percent of state voters want more information about the financial backers of initiative campaigns. To be informed voters, people need to know who is supporting — or opposing — ballot measures as well as independent expenditure campaigns.

Brownley's bill would help provide it. As Louis Brandeis, a U.S. Supreme Court justice in the 20th century said, "Sunshine is the best disinfectant."