He is also the award-winning coauthor of America Unbound: The Bush Revolution in Foreign Policy and former director for global issues and multilateral affairs at the National Security Council.
In 2008, he was the principal author of a Department of Defense funded $7.6 million Minerva Research Initiative grant entitled "Climate Change, State Stability, and Political Risk in Africa.
His latest book, The Empty Throne: America's Abdication of Global Leadership, co-authored with Ivo H. Daalder and released in October 2018.
With Henry J. Aaron and Pietro S. Nivola, he co-edited Agenda for the Nation,[3] which Choice Magazine named “Outstanding Academic Book of 2004.”[citation needed] In 2001, with Michael E. O'Hanlon, he wrote Defending America: The Case for Limited National Missile Defense.
From 1999 to 2003, he served as deputy director and senior fellow in the Foreign Policy Studies Program at the Brookings Institution.