Obama campaign adviser Robert Gibbs tried unsuccessfully on Monday to get Romney campaign adviser Dan Senor to explain why his candidate would not release more tax returns to prove he had broken no laws by hiding money in Swiss bank accounts and a secret Bermuda corporation.

"It was reported that Mitt Romney has taken pretty extraordinary steps to hide the fact that he has a shell corporation in Bermuda," Gibbs explained during a panel with Senor on MSNBC. "We know as a result of good investigating reporting that he's had a bank account in Switzerland and he's got investments in the Caymans."

"Is somebody who has sheltered their income taxes in Switzerland and the Caymans and Bermuda really somebody who's going to get under the hood and get us to a place of tax fairness?" he wondered. "We need to know why he's got that money there. The American people deserve to know if he's sheltering this money somewhere or, quite frankly, is not paying the taxes that he owes. And the only way to do that, quite honestly, is to release more tax returns and show the American people."

Senor responded that Gibbs' assertion was "stunningly dishonest."

"There's nothing secretive about these accounts," Senor said. "The reason we know about these accounts is because they are in the tax returns Mitt Romney released and they were in the federal disclosure form that Mitt Romney -- financial disclosure form that Mitt Romney submitted. ... Are you suggesting that Mitt Romney is guilty of some kind of felony here?"

"Dan, what I'm suggesting is nobody has any idea because the only person with the tax returns is Mitt Romney," Gibbs explained. "Let's understand that the day before Mitt Romney became governor of Massachusetts, he transferred the ownership of this shell corporation in Bermuda to his wife in order to not have to disclose it. The day before he came governor of Massachusetts! The notion that Mitt Romney has been transparent about the fact that he has offshored money all over this world is patently ridiculous, OK?"

Gibbs added: "But look, Dan, I don't know if he's paid money. I don't know if he's getting a tax break. I don't know if he's sheltering money. He gave 23 years of tax returns to John McCain's vetting committee when he wanted to be vice president of the United States. That vetting committee picked Sarah Palin and not Mitt Romney. Did they do that because something they saw in 23 years of tax returns? Why give John McCain 23 years of tax returns and give the American people 2 years of tax returns?"

But instead of addressing the tax returns, Senor pivoted to an Obama campaign ad that Factcheck.org said determined had "thinly supported" claims about Romney outsourcing jobs while he was running Bain Capital.

"But why not release the tax returns?" MSNBC host Mika Brzezinski interrupted.

"Can we call a spade [a spade]?" Senor objected. "Talking about wanting to change the subject, this wave of attacks against Mitt Romney is a distraction from the real discussion, which is we're in a jobs crisis and we're not talking about jobs."

"Dan, release the tax returns," Gibbs pressed. "Put all this to rest. If Mitt Romney's not hiding something in Bermuda and Switzerland and the Caymans, it'll be in the tax returns. Why not simply do it?"

"It sounds like no one -- including you -- are not suggesting based on what he's released in those accounts, he has not paid his taxes fully, he's not paid the taxes that he's owed," Senor replied.

"Why does he have these corporations?" Gibbs continued. "Dan, do you have secret Cayman account? Do you have a company in Bermuda? Do you have a Swiss bank account?"

"This is a distraction from the real issue!" Senor insisted.

"Eventually Dan will answer the question," Gibbs quipped. "It will probably be in reruns."