Shouldn't he and the Dems at least come up with some important reason, like it's a threat to the Union, or the world will come to an end if they don't get to see his tax returns? I mean, just wanting to see them isn't going to hold water in a court of law.
Of course, you know why they want them. It's to pore over them in the hope (if not expectation) of finding some hint of illegality.