An acquittal, a partisan beef, and a single Senator who defied his party

The impeachment saga is over; President Trump has been acquitted. But the intensifying acrimony between Trump and his Democratic rivals was evident at the State of the Union address. He refused to shake the hand of Speaker of the House Nancy Pelosi. She, in turn, ripped up her copy of his prepared remarks. Now Republican Senator Mitt Romney, who broke the party line Senate trial vote, is drawing the President's scorn. Plus, the Iowa caucus results continue to be shrouded in controversy. Is American democracy broken? CNN senior writer Zach Wolf breaks down a historic week in Washington with CNN political director David Chalian and CNN reporter and producer Marshall Cohen. via Knit