What branch of government has the power to declare laws and acts of Congress unconstitutional?

Written in 1787, ratified in 1788, and in operation since 1789, the United States Constitution is the world’s longest surviving written charter of government. Its first three words – “We The People” – affirm that the government of the United States exists to serve its citizens. The supremacy of the people through their elected representatives is recognized in Article I, which creates a Congress consisting of a Senate and a House of Representatives.

The positioning of Congress at the beginning of the Constitution reaffirms its status as the “First Branch” of the federal government. The Constitution assigned to Congress responsibility for organizing the executive and judicial branches, raising revenue, declaring war, and making all laws necessary for executing these powers. The president is permitted to veto specific legislative acts, but Congress has the authority to override presidential vetoes by two-thirds majorities of both houses.

The Constitution also provides that the Senate advise and consent on key executive and judicial appointments and on the ratification of treaties. For over two centuries the Constitution has remained in force because its framers successfully separated and balanced governmental powers to safeguard the interests of majority rule and minority rights, of liberty and equality, and of the central and state governments. More a concise statement of national principles than a detailed plan of governmental operation, the Constitution has evolved to meet the changing needs of a modern society profoundly different from the eighteenth-century world in which its creators lived.

This annotated version of the Constitution provides the original text (left-hand column) with commentary about the meaning of the original text and how it has changed since 1789 (right-hand column).