Chief of Staff Susie Wiles could make or break Trump's second term. NPR's Ailsa Chang speaks with Chris Whipple, author of The Gatekeepers: How the White House Chiefs of Staff Define Every Presidency.

Donald Trump's "ice maiden" Susie Wiles is acting as a gatekeeper for the president including for the the world's richest man Elon Musk who has become a key ally of the Commander-in-Chief ...