Moreover, actual spending could be far higher because the reports cover only spending on communications. There is no accounting for get-out-the vote field operations by conservative and liberal groups.
The money comes amid a new landscape in campaign finance created when the Supreme Court, in a case known as Citizens United v. Federal Election Commission earlier this year, opened the way for corporations and unions to spend money in elections. While that ruling and other court decisions have created a more freewheeling environment, the lack of disclosure makes it difficult to determine whether corporations have stepped up their giving.
What's more, the special Massachusetts Senate election this year, won by Republican Scott Brown, preceded the Citizens United decision and still attracted more than $5 million in spending by more than a dozen outside groups.
The U.S. Chamber of Commerce relies on undisclosed corporate contributions and has seen its fundraising grow. Chamber President Thomas Donohue has aimed for a record goal of $75 million in political spending at the federal and state levels this election season.
Bruce Josten, top lobbyist for the U.S. Chamber, said the business group saw Democratic-allied groups in 2008 pour vast sums of money into TV advertisements and achieve historic successes and decided to "take a page out of their book, learn a lesson."
"We've been able to do what we've done because people are angry," Josten said.
Money alone does not decide political contests. In 1994, the Democratic fundraising advantage could not stop a Republican tidal wave that switched control of Congress.
But it is one significant barometer of partisan fervor.
"Money does follow momentum," Josten said. "You saw that in '08, and you're seeing it now."
Republican-leaning groups have far outpaced liberal and Democratic-leaning organizations. American Crossroads and its affiliate, Crossroads Grassroots Policy Strategies, surpassed their $65 million fundraising goal on Monday and together have spent $30 million on 14 Senate and 18 House races. The Chamber of Commerce has spent $34 million in 58 races. The American Action Network, which occupies the same 12th floor office space in a Washington office building with American Crossroads, has spent $22.7 million.
With days to go, Democratic-allied groups are weighing in, too. They are relying primarily on labor unions that are spending directly in some battleground races or financing smaller versions of the GOP-allied model.
The National Education Association, through its advocacy fund, has pumped $2.4 million into four Senate races just in the past three days, including $1 million for ads opposing Republican Senate candidate Dino Rossi in Washington state. But labor's effort is diffuse. One of the biggest union spenders — the American Federation of State, County and Municipal Employees — has spent $90 million so far in this election, according to the union's political director, Larry Scanlon. But that money includes millions that it is spending on gubernatorial and state legislative races. Its direct spending on congressional contests as of Tuesday totaled $11.8 million.
Unions also are less likely to use television advertising to deliver their message, focusing instead on mailings and door-to-door canvassing.
In addition, the millionaire contributors that helped finance Democratic outside groups in the past have largely stayed away from politics this election, and the unions, their ranks diminished by the recession, have less money to spend. Donors like billionaire George Soros have put their money into policy causes such as health care and climate change. Last week, Soros gave $1 million to the liberal Media Matters for America, a group that routinely targets Fox News. On Tuesday, he contributed $1 million in support of a California referendum to legalize the recreational use of marijuana.