Mitt Romney can't seem to shake questions about his tax returns. The GOP presidential candidate's wife, Ann, chided the press for hounding her husband for more than the two years of returns (2010 and 2011) he is releasing, telling ABC News that Mitt, who's worth an estimated $250 million, has revealed everything "people need to know" about his family's finances. But the furor continued, with former president Bill Clinton, echoing calls from several prominent Republicans, saying that Romney should hand over 10 years of returns. Why won't this story die? Here, five reasons:

1. Democrats know this issue is gold for President Obama

Congressional Democrats are cranking up heat on Romney, says Rosalind S. Helderman at The Washington Post, by proposing legislation that would require all presidential candidates to release 10 years of tax returns. They also want to force disclosure of overseas investments, a way of calling attention to Romney's offshore accounts. Obviously, "Democrats sense they may be getting traction over Romney's refusal to release" more information.

2. The public really wants to know

It's not just Obama and his fellow Democrats who think Romney should open up his tax files, says Susan Page at USA Today. A USA Today/Gallup poll released on Thursday found that a majority of Americans — and that includes a third of Republicans — think that Romney should release more of his tax returns. Forty-two percent don't believe Romney's hiding anything harmful, while 44 percent are convinced that his returns from the years before 2010 contain damaging information. Fifteen percent think the revelations would show Romney is "unfit to be president."

3. Team Romney's errors are prolonging the story

Ann Romney's condescending attempt to put the matter to rest was not helpful, says Janet Shan at Hinterland Gazette. When you run for president, "your life is an open book," so telling Americans they don't need more information is a "slap in the face of all voters." Romney's a rich man, says Chris Cillizza at The Washington Post, so there are "nuggets to be mined" in his financial records, no doubt. But his line about not wanting to give Obama ammunition is only fueling speculation about what he's hiding, and turning what could have been a brief crisis into a slow "political death of 1,000 cuts."

4. Even conservatives are demanding that Romney open up

All the "friendly fire" Romney is taking from Republicans is keeping this issue in the headlines, says Liz Marlantes in The Christian Science Monitor. A parade of prominent Republicans, from former Mississippi governor Haley Barbour to Weekly Standard founder William Kristol, "have been voicing frustration with Mr. Romney for weeks now," urging Romney to make more returns public and fight back more aggressively against Democratic attacks. Granted, a lot of these conservatives have never been Romney fans, but their increasingly stinging remarks are getting attention, which can only hurt.

5. Biased reporters are carrying water for Obama

The "biased and sloppy" media are keeping this story alive, says Jennifer Rubin at The Washington Post, to help Obama drive home his attacks on Romney's taxes and his record at Bain Capital. "If liberals were honest about full disclosure they’d have complained about the Obama administration's serial secrecy and lack of transparency." Romney's right to refuse to bend. Otherwise he'd be letting "the Obama camp and his spinners direct his campaign."

Read more political coverage at The Week's 2012 Election Center.