Constables in the United States
While Constables primarily serve the Courts, they belong to the executive branch of government.
Federal government of the United States
The Judiciary Act of 1789 subdivided the nation jurisdictionally into judicial districts and created federal courts for each district. The three tiered structure of this act established the basic structure of the national judiciary: the Supreme Court, 13 courts of appeals, 94 district courts, and two courts of special jurisdiction. Congress retains the power to re-organize or even abolish federal courts lower than the Supreme Court.