***STORY UPDATES BELOW***

The Obama camp appears to be laying ground for pushing back against Hillary Clinton's latest campaign attacks, even if that means taking a negative approach themselves. The difficulty, as has been noted in the past, is maintaining the positive approach that has dominated his campaign while still drawing contrast with the Clintons.

Obama campaign manager David Axelrod claimed last night:

"If Sen. Clinton wants to take the debate to various places, we'll join that debate. We'll do it on our terms and in our own way but if she wants to make issues like ethics and disclosure and law firms and real estate deals and all that stuff issues, as I've said before I don't know why they'd want to go there, but I guess that's where they'll take the race.''

The Associated Press cites an anonymous Obama aide:

A senior Obama adviser, speaking on condition of anonymity, said Obama's team will respond to Tuesday's results by going negative on Clinton -- raising questions about her tax records and the source of donations to the Clinton presidential library, among skeletons in the Clintons' past.

And Obama is challenging Hillary's claims to be a better Commander-in-Chief:

"I hope people start asking is what exactly is this foreign experience she is claiming," he said. "Was she handling crises during this period of time? I haven't seen any evidence that she is more equipped to handle a crisis.

"She made the experience argument and her ability to handle a crisis, so I think it is important to examine that claim and not just allow her to assert it," he added. "She has made the argument that she is thoroughly vetted. If the suggestion is somehow that on issue of ethics or disclosure or transparency that she is somehow going to have a better record than I have or could (better) withstand Republican attack, then that should be tested."

Meanwhile, the Associated Press is reporting that some superdelegates worry about future attacks. Donna Brazile, a Democratic strategist, had this to say to the Associated Press:

"Despite Obama's impressive victories in February, Clinton's comeback is based on sowing political seeds of doubt," said Donna Brazile, a Democratic strategist and one of nearly 800 party leaders known as superdelegates for their ability to determine the nomination. "In order to clinch the nomination, he must anticipate the worst attacks ever."...

..."If these attacks are contrasts based on policy differences, there is no need to stop the race or halt the debate," Brazile said. "But, if this is more division, more diversion from the issues and more of the same politics of personal destruction, chairman Dean and other should be on standby."

UPDATE: The Obama camp has released a memo criticizing Clinton for refusing to release her tax returns. David Axelrod reinforced the message saying Clinton had "a history of nondisclosure," after promising that "the vetting of Hillary Clinton has yet to start."

Read the memo:

TO: Interested Parties FR: The Obama Campaign RE: TAX RETURNS: What does Clinton have to hide?

DA: March 5, 2008

The Clinton campaign today maintained that "the vetting of Barack Obama has just begun." The truth is, more than a year into this campaign, some very simple vetting of Hillary Clinton has yet to start.

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. 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. Though her campaign has tried to kick the issue down the road, Democratic voters deserve to know, right now, why it is she is hiding the information in her tax returns from last year.

The Clinton campaign has said that they have released copious amounts of financial information but there are many questions about their private dealings that could be answered in their tax returns but not in the information that is currently available. For example, here are eight pieces of information that could be learned from her tax returns, the accompanying schedules, and attachments:

Effective tax rate - including whether or not any tax shelters were used to reduce it
Amount of income for spouses by source
Amount of stock gains and losses
Gross income for the couple
Amount earned from stock dividends
Amount of household employment taxes paid
Personal exemptions taken
Charitable contributions made

Senator Clinton has also claimed that she is too "busy" to release her tax returns. Given the fact she is able to loan her campaign $5 million, you would think the Clintons would be able to hire an accountant. The reality is that she wants to keep this information hidden from voters. The people of Wyoming, Mississippi, Pennsylvania and the rest of the country should wonder why.

The Clintons' record on releasing tax returns:

FEBRUARY 2008: Clinton Reiterated That She Would Not Release Her Tax Records Until She Is The Nominee And Not Before Mid-April. Sen. Hillary Rodham Clinton says she won't release her tax returns until she has the Democratic presidential nomination in hand, and not before tax filing time comes in mid-April. "I will release my tax returns," Clinton said during the debate. "I have consistently said I will do that once I become the nominee, or even earlier." Pressed about the timing of releasing her tax returns, campaign aides were more reticent Wednesday, indicating that Clinton would not release the sensitive financial data during a hotly contested primary, but only at tax filing time. [AP, 2/27/08 ]

JUNE 2007: Clinton Does Not Plan to Release Her Tax Returns Until Next Year. According to the Washington Post, Clinton said through a spokesman that, "like past presidential candidates," she will "release tax information in the election year." [Washington Post , 6/19/07]

APRIL 12, 1996: Clinton Released His Tax Returns. President Clinton and his wife earned $316,074 in 1995, including the president's $200,000 salary, according to tax returns released Friday by the White House. The public release of the tax returns, three days before the April 15 filing deadline, shows that Clinton and first lady Hillary Rodham Clinton are owed a refund of $5,656 on the $81,093 they paid in taxes, and will apply that refund to their 1996 income taxes. [UPI, 4/12/96]

April 15, 1992: Bill Clinton Made His Tax Returns Public. APRIL 15, 1992: Bill Clinton made his tax returns made public. [Los Angeles Times, 4/16/93]

Bill Clinton Released His Tax Returns In 1992 But Refused To Release Their Tax Returns From Before 1980. During the 1992 campaign, the Clintons claimed to be coming clean by releasing their tax returns from 1980 forward. But they steadfastly refused to release their returns for prior years, and only later did we learn that 1978 and 1979 were the tax years when Mrs. Clinton reported her 10,000% cattle-futures trading profit. [WSJ, 2/22/08 ]

UPDATE: The Hillary camp has responded with a statement from Howard Wolfson:

Faced with many legitimate questions about Senator Obama's long-time relationship with indicted political fixer Tony Rezko, the Obama campaign has chosen to lash out at Senator Clinton.

Here are the facts:

Over 20 years of the Clintons' tax returns are in the public domain.

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.