MICHAEL A. SHEEHAN has held the following positions: New York City Deputy Commissioner for Counterterrorism; Assistant Secretary General in the Department of Peacekeeping Operations at the United Nations; Ambassador at Large for Counterterrorism at the State Department; National Security Council staff officer at the White House; and commander of a counterterrorism hostage rescue unit in the U.S. Army Special Forces. A graduate of West Point as well as U.S. Army Airborne, Ranger, and Special Forces schools, Sheehan was deployed in such hot spots as El Salvador, Panama, Korea, and Somalia before...