WASHINGTON - With a week to go before the elections, independent groups, most of them with sharp partisan leanings, have spent $257.7 million to influence political campaigns, nearly quadrupling such interest groups' total spending in the last midterm election, according to a Washington watchdog group.
In 2006, the last nonpresidential congressional election year, the groups spent a total of $68.8 million for the election, according to information from the Center for Responsive Politics, which tracks the data.
Spending by conservative groups this year is more than 2 to 1 ahead of spending by more liberal groups. In 2006, when Democrats regained control of Congress, liberal spending led by about 2 to 1.
The 2010 spending spree is shattering records thanks partly to an unusually competitive year when control of Congress appears up for grabs, but largely due to the Supreme Court's ruling last January in Citizens United v. Federal Election Commission.
The 5-4 decision removed curbs on independent expenditures by corporations and unions, freeing them to spend without limit from their own treasuries on campaign ads and advocacy efforts so long as they aren't coordinated with candidates' campaigns.
Under tax and campaign finance laws, most such groups don't have to disclose their donors until after the election.
Just how much all this spending matters to the outcome of the elections Nov. 2 is unclear.
Experts have long thought that money can help define lesser-known candidates, for better or worse. They also stress that money alone won't win a race, however, particularly since voters often become numbed by repetitive advertising.
"Television ads are important in driving voter perceptions of candidates in a race," said Jonathan Collegio, a spokesman for the groups, though he added, "At a certain point, any advertising will result in diminishing returns, especially in the last weeks of an election cycle."
The other question that the spending barrage raises is whether voters are being badly misinformed, confused by the barrage of charges and countercharges and uncertain whom the groups with haughty-sounding names represent.
"People don't like to think they're being bought," said Trevor Potter, a former Federal Election Commission chairman who's now the president of the nonpartisan Campaign Legal Center.
However, he warned, evidence long has shown that advertising compels people to buy certain products, and "it seems unlikely a lot of those calculations are wrong."
One of the more active independent groups is American Crossroads, a political campaign group whose board chairman is former Republican Party Chairman Michael Duncan, and its sister organization, Crossroads Grassroots Policy Strategies, an issue advocacy organization. Karl Rove, President George W. Bush's political guru, is an informal adviser to both.
"Voters should have a healthy dose of skepticism and a steady finger on the remote to change the channel," said David Levinthal, a spokesman for the Center for Responsive Politics.
Among outside independent groups, the conservative American Action Network is the top spender so far, at $22.7 million, followed by American Crossroads, at $18 million, and Crossroads GPS, at $11.5 million.
Also listed as big spenders are two labor unions friendly to Democrats: the Service Employees International Union, at $11.3 million, and the American Federation of State, County and Municipal Employees, at $10.5 million.
The chief beneficiaries so far have been Senate races in Colorado, where outside groups had poured in $29.7 million as of Monday - with GOP-friendly groups giving slightly more - and Pennsylvania, where $18.8 million has been spent and where Democratic-allied groups have a slight edge.
Outside spending is also heavy in Washington state, with $14.4 million; Nevada, with $14.2 million; and Arkansas, with $13.3 million.
The efforts of Republican challengers Dino Rossi in Washington state and Sharron Angle in Nevada are getting more help than Democratic incumbents are in those states, but in Arkansas, Sen. Blanche Lincoln, though trailing badly in the polls, has seen a slight outside spending advantage.
The House of Representatives race that's attracting the most outside cash has been Nevada's 3rd District battle between incumbent Democrat Dina Titus and Republican Joe Heck. About $6.1 million has been spent, with Titus holding an edge in the district, which stretches from Las Vegas' suburbs to the Arizona border.