White House Senior Adviser David Axelrod continued the administration’s offensive against the U.S. Chamber of Commerce and conservative groups Sunday, saying there had to be a shady reason behind non-disclosure of donors who were helping fund the groups’ campaign ads.

Like last Sunday, when Axelrod told CBS’s Bob Schieffer the burden was on the Chamber to disprove the allegations, Axelrod did not offer proof of the claims that have become a Democratic talking point in the last weeks before crucial midterm elections.

On CNN’s “State of the Union” Sunday, Axelrod instead told host Candy Crowley that journalists needed to probe the source of the groups’ donations. Democrats allege foreign influences and special interests are helping fund a blitz of campaign ads against their party.

“They say, ‘Trust us, trust us, we’re — everything is cool, everything
is kosher, don’t worry about it, but we’re not going to disclose,'” Axelrod said. “Let
me tell you something, people don’t disclose, there’s a reason.”

He also alleged the spending of 501(c) groups coupled with the lack of disclosure might not be on the up and up.

“It’s perfectly legal if they spend a majority of their money on something else,” Axelrod said. “It would be interesting to see if that’s the case.

“You tell me if this is on the up and up,” he added.

On “Meet the Press” Sunday, White House press secretary Robert Gibbs directly called out the executive vice president for government affairs at the Chamber, challenging him to prove the group’s claim that foreign money isn’t used in the funding of its political ad campaigns.

“Bruce Josten could simply open up the books,” Gibbs said. “It’s a pretty easy solution to simply show the American people where the money is coming from.”

Host David Gregory asked Gibbs whether Democrats’ assertions about the Chamber funding ads with foreign dollars are “more smoke than fact.”

“Absolutely not,” Gibbs fired back.

Axelrod responded to a question about whether voters would prefer Democrats focus on issues such as the economy by maintaining it was an issue of the economy, as Republican wins could mean danger for the administration victories of healthcare and Wall Street reform.

“Ask these folks why they feel it’s necessary to keep these funds
secret,” he said. “We tried to make them public, even the Democratic funds —
Democratic-leaning funds. We don’t think anybody should keep these
things secret.”

He called the financing controversy “a threat to our democracy.”

“These secret special-interest funds will have a louder voice in the
last three weeks of this cycle than the Democratic Party did throughout
the cycle,” Axelrod said. “There’s something fundamentally wrong with that.”

Gary Bauer, who serves on the board of the Emergency Committee for Israel, which has been running ads against Rep. Joe Sestak (D) in Pennsylvania’s Senate race, said on CNN that President Obama had received tens of thousands of dollars in donations in his presidential campaign “that he did not disclose the names of,” adding there was evidence that some of it came from foreign citizens.

“So for Mr. Axelrod and these guys suddenly to be on their high horse and say that they’re defending democracy when for years the left has done this including the unions and nobody’s said a word,” Bauer said.

Gibbs didn’t answer the question of whether Democrats who have received the Chamber’s endorsement should reject that backing, though he did acknowledge the Chamber “supported the president’s recovery plan.”

“The chamber certainly has a constitutionally protected right to air ads, but the president has said that groups that support Democrats and Republicans ought to simply tell the American people where they get their money,” said Gibbs.

The Chamber has thrown its support behind a number of centrist Democrats in tough races this fall, including Gov. Joe Manchin (W.Va.) and Reps. Frank Kratovil (Md.) and Glenn Nye (Va.).

This story was updated at 12:25 p.m.