The U.S. Chamber of Commerce says that in this week alone it will spend more than $10 million in U.S. House and Senate races in key states, a massive infusion by the business lobby against Democratic candidates in about 30 contests.
The chamber's spending this week is the biggest of the campaign season by a group other than a national political party, and it represents an escalation in ads by the group, which has expressed a goal of spending $75 million in this year's midterm elections.
This announcement offers further evidence of a big advantage the GOP has over Democrats in the 2010 elections.
A Washington Post analysis this week shows that such spending has overwhelmingly favored Republican candidates, giving the GOP a 7-1 margin over Democrats when the spending comes from cash spent by outside interest groups.
The boost in spending comes as liberal groups raise questions about the chamber's financial sources.
The Center for American Progress and MoveOn.org suggest the trade group could be using foreign money to air the ads, which would be illegal. The chamber denies the claim. It says money raised from foreign corporations is segregated from its political spending. The law does not require the chamber to disclose donor names or the source of the money.
The new ads include $1 million spent against Rep. Paul Hodes, the Democratic Senate candidate in New Hampshire, and $1 million against Gov. Charlie Crist in Florida, the Republican turned independent who is running for the Senate. The ads also take aim at Democrats in Senate races in Colorado, Illinois, Wisconsin, Pennsylvania, Connecticut and Missouri.
In addition, the chamber is airing ads in nearly two dozen House races, including multiple contests in Ohio and Pennsylvania.
The chamber is spending $500,000 for an ad targeting Democratic Senate hopeful Richard Blumenthal in Connecticut as a "sue first and ask questions later" attorney general. The ad says Blumenthal's tenure as attorney general has forced some of those companies to go out of business while under investigation.
Blumenthal is in a tight contest with Republican Linda McMahon, a former professional wrestling executive who has spent heavily from her personal fortune on the campaign.
Another ad takes aim at Democratic Sen. Russ Feingold, fighting a tough re-election battle in Wisconsin.
In the 30-second spot, an announcer laments that "Russ always said he'd change Washington. Looks like Washington changed him." It cites his votes for President Obama's health care overhaul, increasing U.S. debt limits and allowing politicians to spend freely.
Feingold, seeking a fourth term, has run into trouble in his campaign against newcomer Republican Ron Johnson.
Questions about the chamber's foreign money were first raised this week by ThinkProgress, a blog of the liberal Center for American Progress. The account pointed to overseas business councils, known as "AmChams," that pay dues that go into the general fund of the U.S. Chamber of Commerce. MoveOn.org sent a letter to the Department of Justice calling for an investigation.
Chamber spokeswoman Tita Freeman called the claims "unfounded, deceitful and completely erroneous." She said the AmChams collectively pay $100,000 in dues and that the money is used to pay for international programs.
"No foreign money is used to fund political activities," she said.
Freeman dismissed the claim as the work of a "George Soros-funded, anti-business blog," a reference to the billionaire investor known for his support of liberal causes.
NPR's Don Gonyea contributed to this report, which also includes material from The Associated Press