Three of President Obama's nominees for administrative positions have been beset with unpaid tax problems (so far). One has withdrawn.
While people should pay the taxes they owe, the US tax code is also unreasonably complicated. It's not out of the question that someone might miss something. I'm not all that surprised that three of the President's nominees ran into tax trouble.
Edit: Tom Daschle has just withdrawn his nomination as Secretary of Health and Human Services. Oh well.