According to the TSA, watch lists are a critical tool used to keep known terrorists off airplanes and are a key component of aviation security.
The Terrorist Screening Center, which is part of the Federal Bureau of Investigation, maintains the U.S. government's Consolidated Terrorist Watch List. The Terrorist Screening Center allows all government agencies, including the Department of Homeland Security and the Department of State, to run name checks against the same comprehensive list with the most accurate, up-to-date information about known and suspected terrorists.