The Constitution of the United States and the Constitutions of the states are a significant source of law in the administrative context. The principles of separation of powers and federalism embodied in the Constitution are important to the structuring of agencies and, to some extent, in limiting the authority of agencies. Article I of the Constitution establishes many of the powers of the national government, specifically the power of Congress to regulate interstate commerce and other matters.

The concepts of due process of law and equal protection of laws, found in the Fifth and Fourteenth Amendments, are vital limitations on the power of agencies. A statute that establishes an agency and sets forth the responsibilities and authority of that agency is an enabling statute. Congress enacts enabling laws at the federal level and state legislatures do so at the state level.

It is common for Congress to create an agency in one year and then make adjustments to the agency’s authorities and responsibilities in later years. Concern about the growing power of the “administrative state” led to the enactment of the Administrative Procedure Act (APA) in 1946. The APA is the basic law governing the procedures that agencies must use in the performance of their functions.