The United States operates as a constitutional federal democratic republic, where power is divided among three branches: the legislative Congress, the executive led by the President, and the judicial Supreme Court. This federal government shares sovereignty with 50 individual state governments, each mirroring the three-branch structure and holding significant power within their jurisdictions. American politics has been largely shaped by two dominant parties since the Civil War – the left-leaning Democratic Party and the right-leaning Republican Party – which lack a formal central organization, allowing for diverse factions.

While most officials are popularly elected, the President is notably chosen through the Electoral College. This system, along with a powerful Senate and Supreme Court, strong separation of powers, and persistent two-party dominance, makes the U.S. political landscape unique compared to many other developed nations.