The armed confrontation between the PC and Federal and local law enforcement officials on February 13, 1983, is discussed, and some of PC's leaders are identified. 'Posse Comitatus' means 'power of the people within the country.' Members of the PC believe that all legal rights are derived from the U.S. Constitution, the Bible, the Magna Carta, the Articles of Confederation, and Common Law. They consider the sheriff to be the only authorized law enforcement officer in the United States, and reject the court's power to empanel juries. Since they do not acknowledge State and Federal rights to enact laws, PC members assume such laws are unconstitutional and ignore them. Allegations of violations include murder, assault, firearms and explosives, and many State tax and land use laws. All members of the PC must be white, Christian, and interested in the preservation of law and order. The article describes the antisemitic and extremist beliefs to which members adhere. It identifies groups affiliated and associated with the PC, and describes State, local, and Federal law enforcement involvement with the Posse. Attention is focused on the Bureau of Alcohol, Tobacco, and Firearms' (ATF) involvement with the PC; several ATF investigations are detailed. One violation of specific interest to ATF is the conversion of legal semiautomatic weapons to weapons that can fire fully automatically. The article lists the types of firearms recommended by certain PC groups, describes PC paramilitary training camps, and emphasizes the terrorist nature of PC and its threat to society. Included are 42 references.