he can't afford to appear weak. After being so adamant about not releasing any more returns, how can he possibly make the case that he'd be able to stand up to the Chinese? If he caves on this point will he have any credibility left? He drew the the line and Team Obama had the audacity to step over.
Furthermore, if he were to release the returns and, heaven forbid, they contained incriminating information, would that spark more investigation into other areas of his realm? Would anyone ever trust him again?
If he releases the returns and they contain no scandalous information, will his recalcitrance cause the general populace to wonder how that character trait will play out in the White House? If he's so unreasonable about this issue, how unreasonable will he be when there's an issue that more directly affects a citizen's inalienable rights?
Willard's in a corner, folks, and I can't see any way for him to escape without tracking paint everywhere. Ain't it delicious?