To what extent does disorder threaten the global economic system, and must the United States prevent piracy, international crime, and general lawlessness in order to maintain our relative prosperity? Does uncertain access to sources of energy pose a threat to U.S. and global prosperity? The leading advocates of U.S. global primacy contend that trade has expanded because the United States provides a global public good of security within the commons, and that such trade would slow or contract if the United States were to reduce its global policing function. Does global order depend upon a single power enforcing the rules of the game, and is the United States capable of playing this role indefinitely?