The modern constitutional militia movement, the constitutionalist wing of the "militia movement" in the United States, became active in the mid 1990s in a response of outrage about the violent confrontation at Ruby Ridge, the Waco Siege and gun control legislation. The movement is composed largely of veterans, libertarians, and Second Amendment advocates who share a common belief in individual liberties and civil responsibilities, according to their interpretation of the U.S. Constitution, as well as disdain for what are perceived to be abusive, usurpatious, or tyrannical federal government decisions and actions, and a set of ideals associated with the values of the militia they see embodied in the Constitution.
The constitutional militia movement has ideological roots stretching back to the American Revolution, with periods of subsidence and revival. Revivals include Fries Rebellion (1799),the Revolution of 1800, the Dorr Rebellion (1842), the Copperheads (1861–65), and the American Liberty League (1934). Throughout American history, there have been other constitutionalist revivals in opposition to various government actions.
Some writers have asserted that the modern revival of the constitutional militia movement began as early as 1958 but that, in this early phase, it was associated ideologically with the white supremacist Christian Identity movement mixed with constitutionalist elements.
A fear of Communism was prevalent in the United States during the Twentieth Century, against which was set the modern revival of the constitutional militia movement. These militia revivals believed in the sanctity of the U.S. Constitution, and that certain groups are conspiring to destroy America. Unlike the Christian Identity groups, the Constitutionalist militias generally resist casting blame on ethnic, racial or religious groups, but rather blame influential individuals or groups of individuals (e.g., the Bilderberg Group, the Trilateral Commission) who promote globalization, collectively known as the New World Order. The Posse Comitatus is an exception to this principle, however, as it adheres to the antisemitic theory of the Zionist Occupation Government.