Former Defense Secretary Ash Carter says that he could not serve under President Trump, despite serving for five other U.S. presidents, because of Trump's impulses.

Ash Carter, former U.S. defense secretary, discusses with James M. Lindsay what it’s like to run the largest institution in the United States. Carter’s book, Inside the Five-Sided Box: Lessons from a Lifetime of Leadership in the Pentagon, comes out today.

Ash Carter, former U.S. defense secretary during the Obama administration who is currently with Harvard's Belfer Center, joins Squawk Box to discuss his thoughts about lawmakers on Capitol Hill are starting their investigative hearings into the dominance of big tech, the defense sector—including the mega-merger between United Technologies and Raytheon, and to interview Commerce Secretary Wilbur Ross on the on-going China trade negotiations.

Jobs in finance, consulting, technology, or law are appealing to many graduates, and many recent graduates find that they can apply their spirit of public service to these private-sector roles. But few, if any, of these roles satisfy the deep hunger for career purpose as well as working for government.

Former U.S. Secretary of Defense and Inside the Five-Sided Box author, Ash Carter, questions whether the Obama and Trump administrations responded aggressively enough to Russia's continued efforts to meddle in U.S. elections and also talks with Stephen Colbert about how he believes the most qualified people should be admitted into the military, regardless of their gender identity.

Ash Carter on CBS This Morning talking about Inside the Five-Sided Box and security threats around the world. June 10, 2019

Obama-era U.S. Defense Secretary Ash Carter, director of the Belfer Center for Science and International Affairs at Harvard University's Kennedy School and the author of Inside the Five-Sided Box: Lessons from a Lifetime of Leadership in the Pentagon (Dutton 2019), draws on his thirty-six-year history with the Defense Department to explain how it functions and why it matters.

A sampling of recent books from Belfer Center authors and affiliates.

Belfer Center Director Ash Carter focuses in this "From the Director" column on the guiding "spirit of public purpose" that new Harvard Kennedy School graduates will need to bring to their careers, as well as reflecting on some of the older and newer faces that he has seen around the school.