Traffic analysis has been of key importance in providing current information to U. S. military commanders on the identity, location, and movement of opposing enemy forces at the tactical and strategic levels. Although some use was made of the discipline as early as the American Civil War, information derived from traffic analysis was critical in influencing and winning many ground, sea, and air battles of World Wars I and II, Korea, Vietnam, Iraq, and other conflicts. T/A also has been useful in supporting diplomatic initiatives, and, especially during the Cold War, it supported counterintelligence, counterterrorism, and counternarcotics efforts, as well as the country’s response to numerous international crises.