Updated

WASHINGTON -- Two groups that have long advocated public financing of elections plan to spend at least $8 million this year to prod Congress to vote on proposed legislation aimed at reducing the influence of big donations in politics.
The joint effort by Common Cause and Public Campaign, called the Campaign for Fair Elections, will launch its first wave of advertising this week aimed primarily at Democrats who have yet to sign on in support of the bill.
The legislation would give candidates $4 of public financing for every $1 dollar raised through contributions of $100 or less. Participation would be voluntary, and candidates could opt out from the system.
Advocates hope the matching money would be so attractive that it would discourage politicians from having to chase big financial contributions from special interest donors.
Proponents estimate the public infusion of money would cost up to $1.8 billion for every two-year election cycle. David Donnelly, the campaign manager for the Campaign for Fair Elections, said one way to pay for the cost would be with a tax or fee on large government contractors.
The Common Cause-Public Campaign coalition will air ads in television markets in Seattle, Denver, Tallahassee and Washington D.C. and are intended to win the support of Democrats such as Jay Inslee, Rick Larsen and Brian Baird of Washington, Diana DeGette and Ed Perlmutter of Colorado, and Allen Boyd of Florida. More ads in other markets are planned later, Donnelly said.
So far, the legislation has 157 co-sponsors, all but three of them Democrats -- not enough to guarantee passage. Prospects are tougher in the 100-member Senate, where major legislation typically requires 60 votes. The bill only has 21 Senate co-sponsors.
Donnelly and Bob Edgar, a former congressman and now president and CEO of Common Cause, said anti-Washington sentiment, bank bailouts and the Deepwater Horizon oil spill in the Gulf of Mexico make the timing ripe to shake up how politicians raise money.
"Democrats and Republicans who are strongest on reform will buffer themselves against anti-incumbent anger," Edgar said.
Donnelly said the joint campaign expects to spend between $8 million and $15 million this year to promote the legislation. He said $2.5 million of that amount has already been spent.
Among those financing the effort is Arnold Hiatt, the former CEO of Stride Rite Corp. and major Democratic Party contributor who earlier this year urged other big political donors to give only to candidates who committed to support the legislation.