Doesn't block the enforcement of a grand jury subpoena. investigative reporter david cay johnston is one of the very few to uncover any of the president's tax returns. he joins me along with cnn legal analyst shan wu. >> david, if this decision stands, you say president trump could have a serious problem once a manhattan grand jury gets the tax documents. what do you believe they could show? >> well, donald lost two income tax fraud trials, and in one of those trials, the tax return introduced in the case was shown to his longtime, now retired tax preparer, jack mitnick, who testified that was...