Trump will just keep obstructing justice and get away with it, like he did in the Mueller report and with every witness because there are no consequences for him. Rape 20 women, no consequences. Stand in front of the public and ask for foreign government help in hacking emails, no consequences. There is nothing to negotiate, you are letting Trump obstruct justice further with witness negotiations. Don't let him know who you are talking to when and keep him from messing with witnesses. Otherwise, this is pointless. Tell Nancy, she is way beyond the point of impeachment and needs to do her job. She is as worthless, as any Congressional rep that still isn't demanding impeachment.