The Romeny camp's response:

“The Obama campaign’s latest unfounded character assault on Mitt Romney is unseemly and disgusting. Mitt Romney had a successful career in the private sector, pays every dime of taxes he owes, has given generously to charitable organizations, and served numerous causes greater than himself,” said spokeswoman Andrea Saul. “Barack Obama has become what he once ran against — a typical politician willing to use false and dishonest attacks to save his job after failing to do his job. The American people expected more from this president, and he continues to let them down.”

What is she talking about?  What is "unseemly" and "disgusting"?

Asking questions about Romney's off-shore bank accounts, that's what.

Over the weekend, the Obama campaign and national Democrats stepped up their campaign to pressure Romney to disclose more than just one year of tax returns (he's only released 2010's) and to explain his bank accounts and other investments in the Caribbean and Switzerland.  Romney's slogan is "Believing in America" — if that's the case, then why is his money all off-shore?

Maryland Gov. Martin O’Malley said it best: “I’ve never known of a Swiss bank account to build an American bridge, a Swiss bank account to create American jobs, or a Swiss bank accounts to rebuild the levies to protect the people of New Orleans. That’s not an economic strategy for moving our country forward.”

And of course there's also the issue of his enormous $100 million-plus IRA. How, despite a $6000 legal limit on annual contributions to an IRA, did Romney’s IRA grow to over $100 million?  It's certainly possible, but it would require taking advantage of certain tax loopholes unavailable to most Americans.

Why is it "unseemly" to ask these questions?  It goes straight to the heart of Romney's position that he "believes in America".  Nobody is suggesting he did anything illegal; nobody is disputing that he donates to charities.  Nobody is begrudging him his wealth.

But Americans have a right to know if their next President is avoiding paying taxes — even if done so legally — by taking advantage of off-shore accounts and businesses that most Americans can't take advantage of.  That's relevant.

“It isn’t too much to ask that a candidate for president explain why he chose to invest in other countries that are known as tax havens rather than in the United States,” Obama campaign press secretary Ben LaBolt says in this video:

So, rather than being outraged at the question… how about an answer??

This is also relevant given that, as The New York Times reports:

President Obama is changing the subject to tax fairness, calling for a one-year extension of the Bush-era tax cuts for people making less than $250,000. 

Mr. Obama plans to make his announcement at the White House on Monday, senior administration officials said. The ceremony comes as Congress returns from its Independence Day recess, and as both parties and their presidential candidates head into the rest of the summer trying to seize the upper hand in a campaign that has been closely matched and stubbornly static.

It's going to be hard for Romney to argue about "tax fairness" for the wealthy, when the wealthy (like him) can avoid taxes by off-shoring their money.