The Constabulary was modeled on the C.N.A.'s Confederation Bureau of Investigation. C.B.I. Superintendant Geoffrey Prentice's text The Nature of Rebellion was required reading for Constabulary agents, and Prentiss sent Colonel Mark Forsyth to Mexico City to assist Vining in establishing the new organization. To gain support for the Constabulary, Vining chose Benito Hermión, son of former President Pedro Hermión, as its first Commandant.
Hermión turned out to have a talent for investigative work, and under his leadership the Constabulary succeeded in ending Moralista attacks in Mexico City and the U.S.M.'s port cities, confining the movement to the Sierra Madre. However, when the political arm of the Moralistas, the Workers' Coalition, held a convention in Palenque, Chiapas in July 1881, a Constabulary raid on the convention provoked a riot in which twenty-three people were killed, including the leader of the Coalition, José Godoy. This sparked an uprising by Chiapan Mexicanos, which spread to Durango, and from there to parts of the northern states. Vining placed the U.S.M. under martial law, and Constabulary agents were given powers over the regular army.
For the rest of the summer of 1881, Constabulary agents roamed the countryside, holding "courts" which arrested, tried, and executed suspected Moralistas, while rounding up thousands of Mexicanos and imprisoning them in internment camps. When rumors appeared of slave rebellions in Chiapas and Jefferson, Constabulary agents entered the slave areas and began indiscriminate executions of slaves, eventually killing over four thousand.
Following Vining's death by heart attack on 12 September 1881, a Cabinet meeting was held which created the office of Chief of State and appointed Hermión to the position. When the Senate refused to ratify the Cabinet's decision, Constabulary agents were sent to imprison five Liberty Party senators, including Fritz Carmody of Mexico del Norte. By the morning of 17 September, every major Libertarian politician in Mexico City was either imprisoned, in hiding, or dead, and the rump Senate voted to confirm Hermión's appointment as Chief of State.