Bill Taylor was worried about a quid pro quo. Now, the career diplomat is set to testify in front of Congress. What might he reveal about the Trump administration's dealings in Ukraine? Plus, as the scope of the impeachment inquiry keeps growing, the timeline becomes ever murkier. CNN political director David Chalian talks through the latest impeachment developments - including Rudy Giuliani's role at the center of it all - with CNN senior writer Zach Wolf and Washington Post reporter Shane Harris.