Peacekeeping is a useful tool to manage international conflict and maintain truces, but it will only work in a narrow range of circumstances. Peacekeepers can order punitive airstrikes, depose elected leaders, destroy infrastructure, and enforce peace accords not drafted by the warring parties. They have overstepped their bounds, and peacekeeping is now often a euphemism for any multilateral military action. A CIA analyst who worked closely with Reagan, Bush, and Clinton administration officials on UN issues, Fleitz examines how peacekeeping works, the rash of peacekeeping failures since...