By Mike Dunn

PHILADELPHIA (CBS) — The biggest issue hanging over the race for Philadelphia mayor has been the political advertisements paid for by independent committees not affiliated with a candidate.

Today, the City Council president introduced a measure aimed at tackling the problem known as “dark money” — unrestricted expenditures in support of candidates, paid for by independent PACs (political action committees) and not subject to the city’s limits on political contributions.

“I think it’s clearly a way of getting around the legislation that was enacted by the mayor and City Council some time ago,” says City Council president Darrell Clarke.  “It has now created an environment where pretty much everyone else is controlling the dialogue as it relates to the mayor’s race and other races.  We cannot limit their contributions, but we think it should be disclosed.”

The independent PACs do have to reveal the names of their donors, but not until May 8th — just eleven days before this year’s primary.

So, Clarke has introduced a bill to require disclosure that is earlier, and more frequent.

“We think that if a person is interested in a particular candidate, that they should disclose their support,” Clarke said today.  “Essentially, we’ll require periods of disclosure by the contributors, because we want to make sure that we capture those individuals who are putting significant contributions in.”

Clarke admits his proposal comes too late to affect the May primary this year, but he hopes for passage in time for the November general election.

In the race for the Democratic nomination for mayor, at least three independent PACs have reportedly spent millions of dollars in support of certain candidates, primarily state senator Anthony Williams and former city councilman Jim Kenney.  Some of their opponents have called on them to reject the so-called “dark money,” but both candidates claim they have no control over the independent groups.