What's Clinton Hiding?

This is the new mantra of the Obama campaign:

(CNN) – Barack Obama's campaign took fresh aim at Hillary Clinton Wednesday for refusing to release her tax returns, asking in a memo circulated to reporters, "What does Clinton have to hide?"

"In the face of her unwillingness to release her tax returns, Hillary Clinton has made the false case in this campaign that she is more electable because she has been fully vetted," the memo stated. "When it comes to her personal finances, Senator Clinton’s refusal to release her taxes returns denies the media and the American people the opportunity to even begin that process."

David Axelrod, the Obama campaign's chief strategist, also said in a conference call with reporters Wednesday that Clinton has a history of non-disclosure and is the least-vetted candidate in the presidential race.

Clinton had said she will only release her tax returns if she captures the Democratic nomination, though her communications director, Howard Wolfson, issued a statement Wednesday indicating she would do so around April 15.

"Over 20 years of the Clintons' tax returns are in the public domain," he said. "Their tax returns since they left the White House will be made available on or around April 15. This information will be in addition to 15 years of uninterrupted public financial disclosure reports."

"Instead of making false attacks, we urge Senator Obama to release all relevant financial and other information related to indicted political fixer Tony Rezko," Wolfson also said.

I hope the GOP is taking notes. Regardless of whoever the nominee turns out to be the GOP should have an attack plan ready to go, thanks to the infighting Democrats.