Note to the Obama campaign...
Most Americans dislike paying taxes. They understand taxes are necessary, but they themselves don't really like paying them. Many, if not most, find ways to "nibble around the edges", to decrease the taxes they pay, so I suspect most Americans would not be happy with having their own tax returns gone over with a fine-toothed comb.
It is now tax season, so these feelings increase exponentially, especially for middle-aged and older taxpayers, most of whom don't file the 1040EZ form, but itemize. I suspect that by hammering on the Clinton's tax returns, you might in fact be alienating those very people you need to attract to win in Pennsylvania.
Just an FYI.