Erin Burnett Outfront

Source: Trump suggested firing impeachment witnesses; Aides warn this could be perceived as retaliation; Trump attacks Pence aide as "Never Trumper" ahead of testimony; Sources: GOP "shaken" by State department aide's testimony; GOP Lawmakers believe State department aide's testimony was most convincing argument on Trump pressuring Ukraine; Wisconsin Trump voter: Trump has to "work his butt off" to try to win this state back; Conservative Wisconsin voter on impeachment: "I don't think it's a witch hunt... we need to go through this"; Conservative voter on impeachment:" I don't think it's a witch hunt"; Biden on legalizing marijuana: "There's not nearly enough evidence" on whether it's a gateway drug; Biden expresses skepticism on legalizing marijuana; Yang pushes legalization of marijuana after Biden says he needs more evidence it isn't "gateway drug"; Sanders joins Warren in mocking rich critics