The United States is the world's oldest federal constitutional republic.
First, it is federal because a union composed of fifty partially self-governing states and federal one federal district united by a central ("federal") government. The self-governing status of the component states are constitutionally well-established and may not be altered by a independent decision of the central government.
Second, the country is a constitutional republic because it is is a state where the head of state (President) and other officials (Legislative Branch: Senate and House of Representatives) are elected as representatives of the people, and must govern according to existing constitutional law (The Constitution of The United States) that limits the government's power over citizens.
Furthermore, in a constitutional republic, the executive, legislative, and judicial powers are separated into distinct branches and the will of the majority of the population is tempered by protections for individual rights so that no individual or group has absolute power (Checks and Balances). The fact that there is a constitutional law limiting the government's power; makes the country constitutional.
The fact that the head(s) of state (the President, the Head of Congress, and the Chief Justice of the Supreme Court) and other officials are chosen by election, rather than inheriting their positions, and that their decisions are subject to judicial review makes the United States republican.
First, it is federal because a union composed of fifty partially self-governing states and federal one federal district united by a central ("federal") government. The self-governing status of the component states are constitutionally well-established and may not be altered by a independent decision of the central government.
Second, the country is a constitutional republic because it is is a state where the head of state (President) and other officials (Legislative Branch: Senate and House of Representatives) are elected as representatives of the people, and must govern according to existing constitutional law (The Constitution of The United States) that limits the government's power over citizens.
Furthermore, in a constitutional republic, the executive, legislative, and judicial powers are separated into distinct branches and the will of the majority of the population is tempered by protections for individual rights so that no individual or group has absolute power (Checks and Balances). The fact that there is a constitutional law limiting the government's power; makes the country constitutional.
The fact that the head(s) of state (the President, the Head of Congress, and the Chief Justice of the Supreme Court) and other officials are chosen by election, rather than inheriting their positions, and that their decisions are subject to judicial review makes the United States republican.