Henry J. Aaron is a senior fellow in Economic Studies at the Brookings Institution, where he holds the Bruce and Virginia MacLaury Chair. Among his many books are Can We Say No? The Challenge of Rationing Health Care, with William B. Schwartz and Melissa Cox (Brookings, 2006), and Reforming Medicare: Options,Tradeoffs, and Opportunities, written with Jeanne Lambrew (Brookings, 2008). James M. Lindsay is vice president and director of studies of the Council on Foreign Relations, where he holds the Maurice R. Greenberg Chair. He was previously deputy director and senior fellow in Foreign Policy Studies at the Brookings Institution. His books include Defending America: The Case for Limited National Missile Defense (Brookings 2001). In 1996-97, Lindsay was director for global issues and multilateral affairs on the National Security Council staff. Pietro S. Nivola is a vice president of the Brookings Institution, where he is the director of Governance Studies. Among his previous books are Tense Commandments: Federal Prescriptions and City Problems (Brookings, 2002).