The Federal government of Mexico (alternately known as the Government of the Republic or Gobierno de la República or Gobierno de Mexico) is the national government of the United Mexican States, the central government established by its constitution to share sovereignty over the republic with the governments of the 31 individual Mexican states, and to represent such governments before international bodies such as the United Nations. The Mexican federal government has three branches: executive, legislative, and judicial and functions per the Constitution of the United Mexican States, as enacted in 1917, and as amended. The executive power is exercised by the executive branch, which is headed by the president and his Cabinet, which, together, are independent of the legislature. Legislative power is vested upon the Congress of the Union, a bicameral legislature comprising the Senate and the Chamber of Deputies. Judicial power is exercised by the judiciary, consisting of the Supreme Court of Justice of the Nation, the Council of the Federal Judiciary, and the collegiate, unitary, and district courts.