Schumer is ready to negotiate for four witnesses

The president is about to be impeached, yet somehow it's anticlimactic. Still, major questions remain about the inevitable Senate trial. In particular, will there be witnesses? Will we hear from John Bolton and Mick Mulvaney? And is the entire saga finally weighing on Trump? CNN political director David Chalian previews a historic week with CNN senior writer Zach Wolf and CNN White House reporter Sarah Westwood.