A new Democratic TV ad all but accuses the U.S. Chamber of Commerce of using foreign funds to secretly back Republican congressional candidates, igniting a furious round of denials and counter-accusations from Republicans.
Democrats presented no evidence to substantiate the charge. The use of foreign funds for U.S. campaign activities is prohibited.
The Democratic National Committee ad, issued barely three weeks from elections in which their hold on House and Senate majorities appears shaky, calls the chamber "shills for big business" and says it is spending millions from anonymous donors to help GOP candidates.
"It appears they're even taking secret foreign money to influence our elections," the ad says. "It's incredible, Republicans benefiting from secret foreign money."
The commercial's allegations echo remarks that President Barack Obama made in a speech last week. Without mentioning the chamber by name, he said the group takes money from overseas companies and added, "So groups that receive foreign money are spending huge sums to influence American elections, and they won't tell you where the money for their ads come from."
Asked to back up the allegation, White House adviser David Axelrod offered no proof but said, "Why not simply disclose where this money is coming from and then all of these questions would be answered."
Axelrod said corporate interests are spending huge sums to help Republicans in the elections without fully revealing where the cash originates, calling those expenditures "a threat to our democracy."
Democratic officials said the ad would run for a week on national cable television beginning early this week.
Appearing on Sunday talk shows, one leading Republican strategist accused Obama of lying while another used nearly as strong language.
"They have not one shred of evidence to back up that baseless lie," said Karl Rove, who was a top adviser to President George W. Bush.
"Have these people no shame?" Rove said. "Does the president of the United States have such little regard for the office that he holds that he goes out there and makes these kind of baseless charges against his political enemies? This is just beyond the pale. How dare the president do this."
The chamber, one of the nation's most powerful business lobbies, spent more than $10 million in ads last week for candidates in House and Senate races around the country, mostly to help Republicans. That is the biggest one-week expenditure of the campaign so far by anyone but the national political parties. The chamber has not revealed where the money came from and is not required to.
Ed Gillespie, former chairman of the national Republican Party, said Axelrod "is either woefully uninformed or willfully deceptive and dishonest." He said Republicans are following the same rules of disclosure that permitted presidential candidate Obama to not specify where all his contributions came from in 2008, and accused the White House of trying to intimidate its political opponents.
"These ads are not a threat to democracy," Gillespie said of the chamber's efforts. "They may be a threat to their power, but their power and democracy are not the same thing, and it's very revealing that they see it that way."
Chamber officials say that out of the chamber's $200 million annual budget, it receives $100,000 from American business interests abroad. They say that money is used to help finance the chamber's international programs and doesn't use any of it for U.S. political activities.
In a written statement, Tom Collamore, a senior chamber vice president, said the Democratic charges show the party trying to change the subject and said the ad is "ridiculous and false."
"The U.S. Chamber will continue to support candidates from both political parties who support a pro-jobs, pro-growth agenda," Collamore said.
Rove appeared on "Fox News Sunday," while Axelrod and Gillespie spoke on CBS' "Face the Nation."