“Governments are instituted among Men, deriving their just Powers from the Consent of the Governed.” — Thomas Jefferson, the Declaration of Independence
The United States is a federal union of 50 states, with the District of Columbia as the seat of the federal government. The Constitution outlines the structure of the national government and specifies its powers and activities, and defines the relationship between the national government and individual state governments. See more on State and Local Government.
Power is shared between the national and state (local) governments. Within each state are counties, townships, cities and villages, each of which has its own elective government.
Governmental power and functions in the United States rest in three branches of government: the legislative, judicial, and executive.
Article 1 of the Constitution defines the legislative branch and vests power to legislate in the Congress of the United States.
The executive powers of the President are defined in Article 2.
Article 3 places judicial power in the hands of one Supreme Court and inferior courts as Congress sees necessary to establish.
In this system of a “separation of powers” each branch operates independently of the others, however, there are built in “checks and balances” to prevent a concentration of power in any one branch and to protect the rights and liberties of citizens.
For example, the President can veto bills approved by Congress and the President nominates individuals to serve in the Federal judiciary; the Supreme Court can declare a law enacted by Congress or an action by the President unconstitutional; and Congress can impeach the President and Federal court justices and judges.