History shows us that this is a story about empire. For more than a century, major innovations in U.S. intelligence-collection capacity have accompanied major expansions of U.S. influence on the world stage. In some cases, U.S. government agencies used distant theaters to test approaches they would later deploy on the home front. Elsewhere, they helped foreign police build internal surveillance systems. The trainers then returned to work in domestic law enforcement, employing the same practices locally. Either way, U.S. residents should worry. The information-management strategies the U.S. has used in projecting its power abroad have usually come home to roost.