The values and ideals of republicanism are foundational in the constitution and history of the United States. As the United States constitution prohibits granting titles of nobility, republicanism in this context does not refer to a political movement to abolish such a social class, as it does in countries such as the UK, Australia, and the Netherlands. Instead, it refers to the core values that citizenry in a republic have, or ought to have.

The Constitution of the United States is the supreme law of the United States. It superseded the Articles of Confederation, the nation's first constitution, on March 4, 1789. Originally including seven articles, the Constitution delineates the national frame and constrains the powers of the federal government. The Constitution's first three articles embody the doctrine of the separation of powers, in which the federal government is divided into three branches: the legislative, consisting of the bicameral Congress ; the executive, consisting of the president and subordinate officers ; and the judicial, consisting of the Supreme Court and other federal courts. Article IV, Article V, and Article VI embody concepts of federalism, describing the rights and responsibilities of state governments, the states in relationship to the federal government, and the shared process of constitutional amendment. Article VII establishes the procedure subsequently used by the 13 states to ratify it. The Constitution of the United States is the oldest and longest-standing written and codified national constitution in force in the world.