State governments in the United States

State governments of the United States are institutional units in the United States exercising some of the functions of government at a level below that of the federal government. Each state's government holds fiscal, legislative and executive authority over a defined geographic territory. The United States is composed 50 states: 13 that were already part of the United States at the time the present Constitution took effect in 1789, plus 37 that have been admitted since by Congress as authorized under Article IV, Section 3 of the Constitution.

While each state government within the United States holds legal and administrative jurisdiction within its bounds, they are not sovereign in the Westphalian sense in international law which says that each State has sovereignty over its territory and domestic affairs, to the exclusion of all external powers, on the principle of non-interference in another State's domestic affairs, and that each State (no matter how large or small) is equal in international law. Additionally, the member states of the United States do not possess international legal sovereignty, meaning that they are not recognized by other sovereign States such as, for example, France, Germany or the United Kingdom, nor do they possess full interdependence sovereignty (a term popularized by international relations professor Stephen D. Krasner), meaning that they cannot control movement of persons across state borders. The idea of "dual sovereignty" or "separate sovereigns" is derived from the 10th Amendment to the Constitution, which states that "the powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people." Structured in accordance with state law (including state constitutions and state statutes), state governments share the same structural model as the federal system, with three branches of government—executive, legislative, and judicial.

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