trickery, but is it a good idea not to be complying or to be talking about not complying? >> i think that we'll hear vice president biden flesh out his answer a little bit more over the coming days. i suspect that what we've heard so far is shorthand for this larger concept, which is that at trials, the only witnesses who can testify are witnesses who have relevant testimony to offer. joe biden was in no position to observe president trump when he was involved in his escapade in ukraine. joe biden has no relevant testimony to offer on president trump's obstruction of congress by refusing to comply with subpoenas for witness testimony or for documents. so there's really no reason for the vice president to testify. the only reason that he would be called or that perhaps his son, hunter, would be called would be if this was going to be a show trial that was trying to deflect from the president's conduct. joe biden isn't on trial here.