A Constitution is the fundamental set of laws and principles by which a country, state or organization is governed. The word itself comes from the Latin constitui, meaning “to make up.” It is also used to refer to a written document that establishes these laws and principles.
The Constitution assigns most of the executive and legislative powers of the United States to Congress (the House of Representatives and the Senate), while granting the judicial branch its independent power to interpret federal law and oversee the activities of the other branches. The Constitution’s framers designed the system of checks and balances to protect the liberty of citizens against the tyranny of any one branch, or even of the entire national government.
For example, the Constitution provides that Congress must approve any treaty that requires Presidential ratification; the President may veto specific legislation; and the Supreme Court is required to give its advice and consent on key executive and judicial appointments. In addition, the Constitution limits the ability of States to restrict or impede interstate commerce.
The Constitution also guarantees the rights and liberties of all citizens, regardless of race or religion. It prohibits ex post facto laws, which penalize behavior that was legal when it occurred; and bills of attainder, which single out individuals for punishment. These protections are only possible because the Constitution has been ratified by the states.