Some of the basic surveillance and security techniques that are often routinely present in other developed democratic countries are not typically available to the government in the United States due to the nation’s historical development and traditions that have emerged from a distrust of government. The difference in capabilities has gained more significance given the security concerns in the wake of the September 11, 2001, attacks (9/11) and the need to deal with additional attacks linked to terrorist groups and the global jihad. This entry discusses the United States’ surveillance and security capabilities, including associated privacy and civil liberties concerns.