directions. if i could drill down for a second into the question of witnesses, which is clearly one that's going to be coming up as the senate debates what the rules should be. there's a real fundamental difference between the witnesses that appeared in the clinton case and the witnesses that we're talking about here because in the clinton case, everyone agreed upon the fact and they were really there just to present the case to the senators in dramatic fashion whereas in this case we don't know what all the facts are. so those witnesses are there to discover information, not just to present a case. >> jeffrey engel, david gergen, fascinating situation we find ourselves in. thank you so much for being with us tonight. >> thank you, john. >> have a wonderful holiday. next, a rare dissenting voice in the president's base calls for the president's removal from office. that, the backlash to it including from the president to himself, and what it says about the president's political standing. and later, new reporting on just how influential vladimir putin may have been on the president's thinking about ukraine and all that it's led up to. that and more when "360" continues.