The Politics of Mexico take place in a framework of a federal presidential representative democratic republic whose government is based on a congressional system, whereby the President of Mexico is both head of state and head of government, and of a multi-party system. The federal government represents the United Mexican States and is divided into three branches: executive, legislative and judicial, as established by the Political Constitution of the United Mexican States, published in 1917. The constituent states of the federation must also have a republican form of government based on a congressional system as established by their respective constitutions.
The executive power is exercised by the executive branch, which is headed by the President, advised by a cabinet of secretaries that are independent of the legislature. Legislative power is vested upon the Congress of the Union, a two-chamber 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 tribunals.
The politics of Mexico are dominated by three political parties: National Action Party (PAN), the Party of the Democratic Revolution (PRD) and Institutional Revolutionary Party (PRI).