The United States is a federal republic of 50 states, a federal district, five territories and several uninhabited island possessions.[217] It is the world's oldest surviving federation. It is a federal republic and a representative democracy "in which majority rule is tempered by minority rights protected by law."[220] In 2021, the U.S. ranked 26th on the Democracy Index, and is described as a "flawed democracy".[221] On Transparency International's 2019 Corruption Perceptions Index, its public sector position deteriorated from a score of 76 in 2015 to 69 in 2019.[222]
In the American federalist system, citizens are usually subject to three levels of government: federal, state, and local. The local government's duties are commonly split between county and municipal governments. In almost all cases, executive and legislative officials are elected by a plurality vote of citizens by district.
The government is regulated by a system of checks and balances defined by the U.S. Constitution, which serves as the country's supreme legal document.[223] The Constitution establishes the structure and responsibilities of the federal government and its relationship with the individual states. Article One protects the right to the writ of habeas corpus. The Constitution has been amended 27 times;[224] the first ten amendments, which make up the Bill of Rights, and the Fourteenth Amendment form the central basis of Americans' individual rights. All laws and governmental procedures are subject to judicial review, and any law can be voided if the courts determine that it violates the Constitution. The principle of judicial review, not explicitly mentioned in the Constitution, was established by the Supreme Court in Marbury v. Madison (1803)[225] in a decision handed down by Chief Justice John Marshall.[226]