Tribe: Trump's attacks on Yovanovitch are ‘witness intimidation’

06:57

Trump attacked ousted Ambassador to Ukraine Marie Yovanovitch during her testimony, leading Democrats to accuse Trump of witness intimidation that could create another article of impeachment. Laurence Tribe tells Lawrence O'Donnell that Trump's tweets shows he needs to be the center of attention: "It's the way he melts down in the process of being impeached that ultimately will lead to a president's downfall."