Mexico is a federal presidential republic, in which a directly elected President serves as both head of state and head of government, while legislative power rests with a bicameral Congress made up of a 128-seat Senate and a 500-seat Chamber of Deputies. The system is defined by the Constitution of 1917, which divides authority between the national government, 31 states, and Mexico City, and binds the presidency by one of the strictest term limits in the democratic world.
How the Federal System Works
Mexico's official name, the United Mexican States (Estados Unidos Mexicanos), signals its federal design. Power is shared between the central government and 32 federal entities: 31 states, each with its own constitution, governor, and legislature, plus Mexico City, which gained the status of a full federal entity in 2016. Each state controls matters such as local policing, civil registries, and parts of education, while the federal government handles defence, foreign affairs, currency, and national infrastructure.
This structure echoes the model of the United States, but Mexican federalism has historically leaned toward a powerful centre. For much of the twentieth century, governors and the legislature deferred to the President, and only since the 1990s has genuine balance among the branches and levels of government taken hold.
The Presidency and the Executive Branch
The President is elected by direct popular vote for a single six-year term known as the sexenio, with no possibility of re-election — not even after a break. This absolute ban is one of the most distinctive features of Mexican government and is treated almost as sacred, traced to the rallying cry of the 1910 Revolution, "Sufragio efectivo, no reelección" (Effective suffrage, no re-election), a reaction against the decades-long rule of Porfirio Díaz.
There is no prime minister and no vice president. The President appoints a cabinet of secretaries to run ministries, commands the armed forces, and from the National Palace in Mexico City directs the federal administration. Because the same person holds both ceremonial and governing roles, the office concentrates considerable authority, balanced in modern practice by Congress, the courts, and independent agencies.
Congress: Senate and Chamber of Deputies
Legislative power belongs to the Congress of the Union, which has two chambers. The Chamber of Deputies has 500 members serving three-year terms: 300 are elected in single-member districts by first-past-the-post, and 200 are allocated by proportional representation. The Senate has 128 members serving six-year terms, combining seats won directly in each state with seats distributed proportionally nationwide.
This mixed electoral system deliberately blends district representation with proportional seats so that smaller parties gain a voice and no single bloc easily dominates. Both chambers must approve federal legislation, while the Senate ratifies treaties and confirms certain senior appointments, including Supreme Court justices.
The Judiciary and Independent Institutions
The judicial branch is headed by the Supreme Court of Justice of the Nation, which rules on constitutional questions and can strike down laws that violate the 1917 Constitution. Justices have traditionally been nominated by the President and confirmed by the Senate, though Mexico has debated and enacted significant reforms to how judges are selected.
Elections are run by the National Electoral Institute (INE), a constitutionally autonomous body widely credited with making Mexican votes credible after decades of distrust. Other independent agencies oversee transparency, competition, and human rights, forming a layer of checks that operate outside the three classic branches.
From One-Party Rule to Multi-Party Democracy
Modern Mexican government grew out of the Revolution and the landmark 1917 Constitution, one of the first in the world to guarantee social rights such as public education, labour protections, and land reform. From 1929 to 2000, the Institutional Revolutionary Party (PRI) won every presidential election, a 71-year grip so complete that the writer Mario Vargas Llosa famously called it "the perfect dictatorship."
The turning point came in 2000, when opposition candidate Vicente Fox of the National Action Party (PAN) won the presidency, confirming a true multi-party system. Today the major forces are MORENA, PAN, and the PRI, alongside smaller allied parties. Power has since alternated between rival movements, though the country still faces challenges including violence against journalists in regions affected by organized crime. For broader context, see our mexico country guide.
Frequently Asked Questions
What type of government does Mexico have?
Mexico is a federal presidential republic. A single elected President leads the executive branch, a bicameral Congress makes laws, and an independent Supreme Court interprets the 1917 Constitution.
How long is a Mexican president's term?
The President serves one six-year term, called a sexenio, and can never be re-elected. There is no vice president, so a successor is chosen by Congress if the office becomes vacant.
What are the two houses of the Mexican Congress?
The Congress of the Union consists of the Senate, with 128 members, and the Chamber of Deputies, with 500 members. Both use a mix of direct and proportional representation.
Where is the seat of Mexico's government?
The capital and seat of government is Mexico City. The President works from the National Palace, built on the site of the Aztec emperor Moctezuma's residence and decorated with murals by Diego Rivera.
