West Wing stars Martin Sheen, AKA President Bartlet, and Mary McCormack, AKA Deputy National Security Adviser Kate Harper discuss the momentum behind the Harris campaign and new book "What's Next: A Backstage Pass to The West Wing, Its Cast and Crew, and Its Enduring Legacy of Service." » Subscribe to MSNBC: youtube.com/msnbc Download our new MSNBC app for the latest breaking news and daily headlines at a glance: msnbc.com/information/download-msnbc-app-n1241692 Follow MSNBC Show Blogs MaddowBlog: msnbc.com/maddowblog ReidOut Blog: msnbc.com/reidoutblog MSNBC delivers breaking news, in-depth analysis of politics headlines, as well as commentary and informed perspectives. Find video clips and segments from The Rachel Maddow Show, Morning Joe, The Beat with Ari Melber, Deadline: White House, The ReidOut, All In, Last Word, 11th Hour, and Alex Wagner who brings her breadth of reporting experience to MSNBC primetime. Watch “Alex Wagner ...