a three-judge panel hearing arguments over the new york d.a.'s subpoena of the president's tax returns this summer. the president's lawyers are trying to keep those private after a lower court ruled against them. this has become a battle over the scope of presidential immunity which is likely headed for the supreme court. further insight today into the turmoil in the trump cabinet, why it's been such a revolving door. >> what led me to resign is there were a lot of things that there were those in the administration who thought that we should do. just as i spoke truth to power from the very beginning, it became clear that saying no and refusing to do it myself was not going to be enough. so it was time for me to offer my resignation. that's what i did. >> up next, more details on the dramatic testimony of bill taylor and why it is so damaging to the president.