Legal Definitions - Plenary power

Plenary power refers to a complete and absolute authority over a particular subject matter, without any limitations or restrictions from other governmental bodies within that specific domain. When an entity possesses plenary power, its decisions and actions within that defined area are considered final and comprehensive, generally not subject to challenge or override by other authorities, except perhaps through constitutional amendment or judicial review of the scope of that power itself.

• Example 1: Federal Immigration Power

  The U.S. Congress holds plenary power over immigration and naturalization. This means Congress has the full and exclusive authority to pass laws determining who can enter the country, under what conditions, how long they can stay, and the process for becoming a citizen. Individual states cannot create their own immigration policies that contradict or undermine federal law; their role is generally limited to enforcing federal statutes.

  This example illustrates plenary power because Congress's authority in this area is comprehensive and exclusive. States cannot independently decide to admit or deny immigrants, or establish their own citizenship requirements, as that power rests solely and completely with the federal legislature.

• Example 2: Tribal Sovereignty over Internal Affairs

  Federally recognized Native American tribes often possess plenary power over their internal governance. This includes matters like determining tribal membership, establishing family law within the reservation, and administering justice for tribal members on tribal lands. State governments typically cannot interfere with these internal tribal decisions or impose their laws on these specific tribal matters.

  Here, the "particular area" is the internal affairs of the tribe. Within this scope, the tribe's authority is complete and not subject to state law, demonstrating plenary power because their decisions in these internal matters are supreme and unrestricted by external state authority.

• Example 3: Federal Government's Power over Treaties

  The U.S. federal government, specifically the President with the advice and consent of the Senate, holds plenary power to negotiate and ratify treaties with foreign nations. Individual states do not have the authority to enter into their own treaties or international agreements with foreign countries.

  This demonstrates plenary power because the federal government's authority to conduct foreign policy through treaties is exclusive and comprehensive. States cannot act independently in this domain, confirming the federal government's complete and unrestricted control over this specific area of international relations.