The United States Politics and Elections begins with primary elections and caucuses, with candidates participating in campaigns and debates. US politics are shaped by two major political parties: Democrats and Republicans, also shaped by special interest groups, lobbyists, and the media. The citizens elect representatives to national, state, and local government, influenced by a diverse society, and citizens’ competing interests are reflected in politics. The United States Constitution stipulates that a presidential election is to be held once every fourth year, with the President and Vice-President positions’ election done long before election day. The US Federal Government is composed of three distinct branches—legislative, executive, and judicial—whose powers vested in the Congress, the President, and federal courts and the Supreme Court.