Nov. 1 (Bloomberg) -- Former ``Sopranos'' television star Vincent Curatola has a new role: Helping the U.S. Chamber of Commerce try to stop Senate Democrats from winning a 60-vote supermajority.

Curatola appears in a television ad aimed at the re- election race of Norm Coleman of Minnesota as part of the chamber's more than $35 million campaign to aid primarily Republican Senate candidates. The largest U.S. business lobby wants voters to elect enough Republicans to block legislation, through a legislative technique known as a filibuster, which would make it easier for workers to form unions. It takes 60 votes to overcome a filibuster.

Many independent groups this year are focusing their advertising on congressional races instead of the campaign between John McCain and Barack Obama. While the 2004 presidential race saw the growth of such groups as Swift Boat Veterans for Truth, which opposed Democratic nominee John Kerry, both major nominees this year discouraged their donors from funding independent ads.

``There is a sense from the top of the ticket that their participation was not wanted nor desired'' in the presidential race, said Sheila Krumholz, executive director of the Center for Responsive Politics, a Washington-based group that tracks campaign finance. ``Clearly, there's been a shift away from these organizations.''

On the other side, the AFL-CIO is spending $53.4 million for 12 Senate and more than 60 House races, plus the presidential campaign.

There is excitement about ``electing progressives who for the first time in eight years will stand with workers and pass policy that begins to give workers a fair shot,'' AFL-CIO political director Karen Ackerman said.

Secret Ballot

Chamber of Commerce spokesman J.P. Fielder said its main goal is to stop a measure requiring companies to recognize unions that obtain a majority of workers' signatures for membership, instead of holding a secret-ballot vote. The way to do that is to deny Democrats the 60 Senate seats they need to force a vote.

The House last year passed the measure, one of organized labor's top priorities, only to see it die in the Senate when Democrats mustered just 51 of the 60 votes needed to bring it to the floor.

``Without a doubt, the business community has come out in force to educate voters on where the candidates stand on specific issues,'' Fielder said. ``We've put boots on the ground, we've put ads on the airwaves and on the Web, we've put flyers in mailboxes.''

Vulnerable Republicans

The chamber is trying to protect vulnerable Republican Senate seats. Of the 12 most competitive Senate races, 11 are held by Republicans. The chamber also has endorsed four Senate Democrats.

The chamber helped fund a group called the Coalition for a Democratic Workplace, which ran the ads featuring Curatola. In addition to Coleman, Republican senators getting a boost from the chamber include John Sununu in New Hampshire and Elizabeth Dole in North Carolina.

In 2004, the chamber gave $3 million to the November Fund, which targeted Democratic vice-presidential nominee John Edwards, a former trial lawyer. This time the November Fund is inactive and the chamber is staying out of the presidential race.

One type of independent group that buys election advertising is the so-called 527 group, named after a provision of the U.S. tax code, which must disclose its donors. Such groups are favoring Democrats over Republicans, $118 million to $45 million, according to the Campaign Finance Institute, a Washington-based research group.

AFSCME and SEIU

The two biggest 527s are operated by the American Federation of State, County and Municipal Employees, which has spent $25.3 million this year, and the Service Employees International Union, which has spent $25.3 million, according to the Campaign Finance Institute.

Spending by 527 groups dropped to $198.8 million in 2008 from $442.5 million in 2004, according to the Center for Responsive Politics. Some groups that bought ads in the 2004 presidential race have gone out of business, including the Swift Boat Veterans and America Coming Together, which supported Kerry.

While money flowing to 527s is down, this election season has seen the proliferation of another type of group incorporated under Section 501(c) of the tax code.

Unlike 527 organizations, 501(c) groups don't have to disclose their donors, and the Campaign Finance Institute estimates that such groups have spent at least $165 million.

One 501(c) organization is Freedom's Watch, formed by supporters of President George W. Bush, including former White House press secretary Ari Fleischer. The organization ran ads in four Senate and seven House races, all in seats held by Republicans. It spent about $9 million, the Campaign Finance Institute said.

Bill Allison, a senior fellow at the Sunlight Foundation, a Washington-based watchdog group, said the record $600 million raised by Obama for his campaign might have drowned out 527 ads in any case, and some Republicans may not have wanted to open their checkbooks for McCain.

``It may well be that there's not a whole lot of enthusiasm for McCain among the folks who would make those type of ads,'' Allison said.

To contact the reporters on this story: Jonathan D. Salant in Washington at jsalant@bloomberg.net; Timothy J. Burger in Washington at tburger2@bloomberg.net.

Last Updated: November 1, 2008 00:01 EDT