witness in mueller's investigation. former white house counsel don mcgahn. the committee chairman, jerry nadler is going to be here live tonight in just a couple of minutes. he's one of those two interviews we've lined up for the show tonight. you will want to see my interview with chairman nadler tonight. mr. nadler and his committee clearly see this lawsuit they have just filed concerning don mcgahn's testimony, they clearly see this as kind of their big kahuna as the thing they have been building up to. they believe this effort to force mcgahn to testify will not only succeed but if it does it'll essentially be the key that unlocks all the other witnesses they want to talk to. and that will thereby setup all the hearings they want to hold about the president's behavior. so those things are both happening sort of now all of a sudden. but one of the other things you should know about, what they've just done with this lawsuit is that for all the huffing and puffing and barrels of ink spilled and pointless panel conversations about whether or