Mexico's government: why nobody is allowed to stay

What the constitution was written to prevent

The Political Constitution of the United Mexican States was published in 1917, at the close of a revolution that had begun as an argument about one man refusing to leave. Porfirio Diaz had monopolised the presidency for more than twenty-five years. The plan Francisco Madero issued from jail on 5 October 1910, the Plan de San Luis Potosi, declared the Diaz presidency illegal and carried the slogan Sufragio Efectivo, No Re-eleccion, effective voting and no re-election. That sentence is what the Mexican political system was built to enforce, and it is still the load-bearing rule inside it.

The principle then had to survive the revolutionaries themselves. A constitutional amendment allowed the outgoing president Plutarco Elias Calles to designate a former president, Alvaro Obregon, as his successor in 1928. Obregon was elected and assassinated before he could take office. The succession crisis that followed produced two answers at once. Calles brought the regional strongmen into a single party in 1929, the Partido Nacional Revolucionario, to settle who would follow whom. At the same time the constitution was revised back to strict no re-election, closing the door Obregon had walked through.

The party is the subject of Mexico: history. The rule is the subject of this article, because the party has been out of the presidency since 2000 and the rule is still running. One consequence is visible in the comparison with the rest of the region: the Mexican military has not openly interfered with elections or governance since the 1920s, a record that holds through decades when coups were ordinary elsewhere in Latin America.

How the presidency is made deliberately temporary

One office is both head of state and head of government: the president appoints the cabinet, commands the armed forces, and may issue reglamentos, executive decrees that carry the force of law. Against that concentration the constitution sets a single limit and applies it without exception. The term is six years, it is served once, and no person who has held the office may hold it again, including anyone who held it on a caretaker basis for a matter of weeks.

There is no vice president. If a president dies, resigns or is removed, the Congress of the Union sits as an electoral college and designates a provisional successor by absolute majority. That is the one occasion on which any Mexican office is filled other than by a direct vote. Every federal, state and municipal election is direct, with no standing electoral college of the kind used in some presidential systems.

The term is fixed firmly enough that a change to the electoral calendar shortens a presidency instead of extending one. The term of Andres Manuel Lopez Obrador ran from 1 December 2018 to 30 September 2024, five years and ten months, because a constitutional change moved the handover forward. Federal elections had traditionally fallen on the first Sunday of July; the new law places them on the first Sunday in June.

The prohibition reaches every level at once. Governors are elected for six years and may not be re-elected. State congresses and municipal governments run on three-year terms. Whatever else Mexican politics argues about, the argument is conducted by people who know the date their own office ends.

How the Congress of the Union is filled

Legislative power sits with the Congress of the Union, a two-chamber legislature made up of the Senate of the Republic and the Chamber of Deputies. Both are filled by parallel voting, which combines plurality contests in geographic districts with proportional representation from closed party lists. The mixture is different in each chamber.

The first-minority senators are the unusual element. Each state automatically sends one senator from the party that came second, which guarantees an opposition presence in the upper chamber whatever the plurality contests produce. The Senate is renewed in full alongside the presidency. The Chamber of Deputies turns over twice as often, so a government meets a national verdict at the midpoint of every presidential term.

Until 2018 no deputy or senator could succeed themselves immediately. That produced a legislature of newcomers every three years, with no accumulated procedural memory to set against an executive that had six. Since the change both may serve up to twelve consecutive years. The reform reversed a century of Mexican constitutional instinct, on the argument that a chamber strong enough to check a president needs members who have been there before.

Beyond legislating, the Congress declares war, imposes taxes, approves the national budget, ratifies international treaties and confirms diplomatic appointments.

Why Mexican judges now stand for election

In September 2024 Congress approved a constitutional reform that placed every federal judge on the ballot: district and circuit judges, magistrates, the members of the Federal Electoral Tribunal, and the justices of the Supreme Court of Justice of the Nation. Candidates are pre-selected by Congress and then chosen by popular vote. The Supreme Court was reduced from eleven justices to nine, and its members serve a single twelve-year term. The first judicial election was held in 2025.

The arrangement it replaced was appointment: justices nominated by the president and confirmed by the Congress, with a Federal Judicial Council managing the careers of the judges below them. The same reform created a Judicial Disciplinary Tribunal and widened the categories of offence that carry mandatory pretrial detention.

The case for the change rests on a documented failure. Few Mexicans have strong confidence in the police or the courts, a large share of crimes therefore goes unreported, and the professional career judiciary had uneven success against corruption and organised crime. The case against it was put by observers who told Freedom House in 2024 that electing judges would threaten judicial independence, and by human rights organisations objecting to the expansion of pretrial detention. This article records both readings and settles neither.

Two further changes from the same period belong beside it. The September 2024 package moved control of the National Guard to the Ministry of National Defence, formalising military command of a force created in 2019 out of the disbanded Federal Police, and gave the armed forces expanded powers of domestic law enforcement. In November 2024 Congress abolished several autonomous bodies, among them the national access-to-information institute. Taken together the three shift authority towards elected majorities and away from insulated appointed institutions, which is either the 1917 logic carried to its conclusion or its inversion, depending on who is describing it.

Who runs Mexican elections and who votes

Federal elections are organised and supervised by the Instituto Nacional Electoral, an autonomous public body. Its predecessor, the Instituto Federal Electoral, was created in 1990 to take the administration of elections out of the interior ministry after the presidential election of 1988, when the counting system failed in the middle of the count, reported at the time in the phrase se cayo el sistema, and left the official result permanently disputed. Each state runs its own electoral institute for state and municipal contests, and Mexico City has one of its own.

Suffrage is universal, free, secret and direct from the age of eighteen. Voting is compulsory in law and unenforced in practice. Registration is automatic, because the national identity document is also the voting credential, so no citizen signs up separately before an election. Mexicans living outside the country, including several million in the United States, may vote by post.

Party registration runs through the same institute. A party must be registered with it and must take at least 3% of the vote at a federal election to keep that registration, which is why the Green Ecological Party lost its registry at two consecutive elections before holding it continuously from 1993. Registered parties receive public funding. Since the reforms the parties negotiated between 1995 and 1996, public money has predominated over private contributions, auditing has tightened, and the courts have held expanded authority to hear electoral complaints brought by individuals and groups.

The franchise arrived in stages. Women could vote in Yucatan from 1917, in local elections and for local office across the country from 1947, and in national elections after a constitutional amendment in 1953. Many states now cap the share of candidates of any one gender at 70 or 80%. After the elections of June 2024 both chambers of Congress reached gender parity, and women won four of the nine governorships contested that month.

How the party system was rebuilt

The PRI held close to hegemonic power at state and federal level through the twentieth century, and the erosion of it is datable year by year. The first state governorship won by an opposition party was Baja California in 1989. The PRI lost its absolute majority in the Congress of the Union in 1997. In 2000 Vicente Fox of the PAN won the presidency with 42.5% of the vote against 36.1% for the PRI candidate and 16.6% for the candidate of the PRD, ending seventy-one years of continuous rule by one party in an election monitored by tens of thousands of Mexican and international observers.

The parties that took its place carry their own genealogy of splits. The PRD was founded in 1989 by members of the PRI who had backed Cuauhtemoc Cardenas against the party leadership in the disputed election of 1988. Morena grew out of a dispute between Andres Manuel Lopez Obrador and other PRD leaders after the presidential election of 2012, won official recognition in 2014, and won the presidency in 2018 and again in 2024. In June 2024 Claudia Sheinbaum was elected with close to 60% of the vote, the first woman elected to the office, and a Morena-led coalition took large majorities in both chambers.

Coalitions are formed for particular elections, identify themselves by a name and a logo, and receive proportional seats according to their combined vote before redistributing those seats among their member parties. A coalition that wins together has no obligation to govern together afterwards. Across the states in 2026 the distribution was Morena in twenty-three, the PAN in four, the PRI and Citizens' Movement in two each, and the PVEM in one.

How power is shared with the states

Mexico is a federation of thirty-one states together with Mexico City, which belongs to the federation as a whole and not to any single state. Each state has its own constitution, its own unicameral congress and its own judiciary, and each may raise local taxes. Governors are elected directly for six years and state deputies for three. Below them sit more than two thousand municipios, the smallest unit of Mexican government, each run by a municipal president elected by plurality for a three-year term.

Federalism on paper has had a centralising history in practice. State and local budgets depend heavily on funds allocated federally, and under PRI rule presidents influenced or decided many state and local matters, including elections. That degree of central control is no longer generally accepted, though the principal parties still hold locally dominant bases in particular states and cities.

Mexico City is the sharpest case. As the Federal District its autonomy was limited by comparison with the states. It dropped that designation in 2016 and has since been acquiring the attributes of a federal entity, with a constitution and a congress of its own, while remaining the seat of the federal government and the one capital in the country that answers to the federation directly.

Where Mexico stands in the world

Mexican foreign policy is written into the constitution. Article 89, Section 10 binds the president to a named list of principles: respect for international law and the legal equality of states, respect for their sovereignty and independence, non-intervention in the domestic affairs of other countries, peaceful resolution of conflicts, and the promotion of collective security through active participation in international organisations. The Estrada Doctrine has served as the working complement to those principles since the 1930s.

Mexico was a founding member of the United Nations, joining on 7 November 1945, and of the Organization of American States, which it joined in 1948. It is also a founder of the Organization of Ibero-American States, of OPANAL and of the Community of Latin American and Caribbean States. It joined the Asia-Pacific Economic Cooperation forum on 17 November 1993 and the World Trade Organization on 1 January 1995, sits in the G20, and has been a member of the OECD since 1994, the only member from Latin America until Chile joined in 2010. It holds observer status at the Council of Europe.

The most durable commitment is a refusal. Mexico has the industrial capability to build nuclear weapons and gave up the option under the Treaty of Tlatelolco in 1968, undertaking to use nuclear technology only for peaceful purposes, and it has signed the United Nations treaty on the Prohibition of Nuclear Weapons. Military expenditure ran at around 0.6% of gross domestic product as of 2023.

Trade agreements do much of the practical work of Mexican foreign relations. The North American Free Trade Agreement came into force on 1 January 1994 and was succeeded by the United States, Mexico, Canada Agreement in 2020. Mexico holds free trade agreements with more than fifty countries, an arrangement made unavoidable by the northern border described in Mexico: geography.

What outside assessments actually record

Observers agree about the shape of the problem and disagree about its direction. Freedom House has treated Mexico as an electoral democracy since 2000, noting that power has alternated between parties at both federal and state level, and in its report covering 2024 it scored the country 26 out of 40 for political rights and 33 out of 60 for civil liberties, in the band it labels partly free. The V-Dem democracy report identified democratic backsliding beginning around 2019.

Both point at the same gap, between electoral machinery that works and a rule of law that does not. The electoral process of June 2024 drew no serious challenge to its result, and hundreds of instances of political violence were recorded during the same campaign. Around 100,000 people were officially listed as missing as of May 2022, and demonstrations across the country in August 2025 put the figure at 130,000 disappeared since 2007. More than a hundred journalists and media workers have been killed or disappeared since 2000, and most of those cases were never solved.

Public opinion tracks the gap closely. A survey by the National Autonomous University of Mexico in 2017 found that 74% of respondents believed the electoral system was not transparent and distrusted the official results. An Enkoll poll in 2026 recorded the main political issues as crime, corruption and the economy. Mexico solved the problem of the permanent president in 1917 and has been arguing ever since about whether the same instrument, an election, can be made to solve the rest.