>> reporter: good morning, alisyn. it was going to be a busy day, but not. these are the four white house witnesses that were going to be testifying, all of them, citing reasons, executive privilege, defying subpoenas, saying they want their own white house attorneys. those individuals, robert blair, senior adviser to the acting chief of staff, mick mulvaney, john eisenberg, nsc top legal adviser, michael ellis, deputy legal adviser, and brian mccormack, the director of the office of management and budget. what is most significant is john eisenberg. he is the one that fiona hill, trump's top russia adviser and colonel alexander vindman, the ukraine expert, approached over their concerns about trump's telephone call with the ukrainian leader. he is also the one who told vindman not to discuss this call. and he's mentioned in the testimony as someone responsible for taking that phone transcript and moving it into a classified server. what was he trying to hide?