Mexico operates as a Federal State, comprised of thirty-two entities: thirty-one states along with Mexico City, which serves as the Federal District and the seat of the Federal Branches. The nation’s governmental framework is presidential, mirroring the principle of separation of powers among the Executive, Legislative, and Judicial branches at both the federal and state levels. This structure ensures a balance of authority and responsibilities across different arms of government.
The Federal Executive power is embodied by the President of the United Mexican States. Similarly, each of the thirty-one states is headed by a Governor, while the Federal District is governed by a Chief of Government. All these executive leaders are elected for a single six-year term, with no possibility of re-election, reinforcing a system of term limits.
Mexico’s Federal Legislative Branch is known as the Union Congress. It’s bicameral, consisting of an Upper Chamber (Senate) and a Lower Chamber (Chamber of Deputies). In contrast, the legislative branches of the thirty-two states are unicameral. The thirty-one states have local congresses, while the Federal District has a Legislative Assembly. Legislators at the state level are elected for three-year terms, while Senators serve for six years, creating different cycles of political renewal.
The Judicial Branch at the federal level is the Supreme Court of Justice of the Nation. It is composed of eleven ministers appointed for fifteen-year terms. These ministers are nominated by the President and then elected by a two-thirds vote of the Upper Chamber, ensuring a degree of consensus in their selection. Each of the thirty-two states also has its own Supreme Court of Justice, mirroring the federal structure.
A cornerstone of Mexico’s political organization is the municipality. The Constitution mandates that all states adopt the municipality as the foundation for territorial, political, and administrative divisions. Currently, Mexico is divided into 2,441 municipalities, each administered by a municipal Town Hall. These Town Halls are elected through public and direct voting and are composed of a Municipal President along with a variable number of officers and trustees, forming the base level of democratic governance.
The Structure of Federal Branches in Mexico
The Mexican Constitution firmly establishes elections as the sole legitimate method for constituting and renewing the Federal Executive and Legislative Branches, as well as state and City Council positions. This commitment to electoral processes underscores the democratic foundations of the Mexican government, overseen in many aspects by institutions like the Ine Mexico (Instituto Nacional Electoral). While this article delves into the structural organization, it’s important to acknowledge the role of INE Mexico in ensuring the integrity and fairness of these electoral processes, although the original text does not explicitly focus on the INE Mexico.
The Executive Branch: The President of Mexico
At the apex of the Federal Executive Branch is a single individual: the President of the United Mexican States. The President is not only the head of government, leading the administration of the Republic, but also the Chief of State and the Commander-in-Chief of the armed forces. Elected every six years through direct, universal suffrage and based on a simple majority, the President’s role is central to Mexican governance. The Constitution strictly prohibits presidential re-election in any form, limiting terms to ensure rotation of power.
The Legislative Branch: Congress – Senate and Chamber of Deputies
The Federal Legislative Branch is vested in the bicameral Union Congress. This Congress is divided into two chambers: the Lower Chamber, known as the Chamber of Deputies, and the Upper Chamber, the Senate. This bicameral structure is designed to provide checks and balances within the legislative process.
Composition of the Lower Chamber (Chamber of Deputies)
The Chamber of Deputies consists of 500 members, all of whom are elected to three-year terms. Deputies are not eligible for immediate re-election, promoting turnover and preventing entrenchment. The composition of the Chamber of Deputies is determined by a mixed electoral system, combining elements of majority rule and proportional representation to ensure diverse representation.
Out of the 500 seats, 300 are filled through relative majority voting in single-member districts. This means that in each of the 300 districts, the candidate who receives the most votes wins. The remaining 200 seats are allocated through proportional representation, using party lists in five multi-member districts, each with 40 seats. This system is designed to achieve a high degree of proportionality between the national vote share of political parties and their representation in the Chamber.
The Constitution includes specific provisions to prevent any single political party from dominating the Chamber of Deputies. No party can hold more than 300 seats in total, combining both majority and proportional representation seats. This rule is significant because while a party might achieve an absolute majority (251 seats), it is prevented from reaching the qualified majority (two-thirds of seats) needed to unilaterally approve constitutional reforms.
Further ensuring proportionality, a general rule prevents a political party’s total number of seats in the Chamber from exceeding its national vote percentage by more than eight points. For example, if a party wins 35% of the national vote, it cannot hold more than 43% of the seats (215 out of 500).
Inside the Mexican Chamber of Deputies, showcasing the legislative plenary hall.
An exception to the proportionality rule exists if a party wins a significantly higher percentage of seats through relative majority voting in single-member districts than its national vote share would suggest. For instance, if a party wins 235 single-member districts (47% of the total) with only 35% of the national vote, the 8% proportionality rule would not apply, even though the difference between vote share and seat share is 12%. This nuanced system reflects the complexities of balancing majority rule with proportional representation.
Members of the Federal Chamber of Deputies are barred from immediate re-election for the term directly following their service. However, substitute deputies who have never held office are eligible to become holder deputies for the immediate subsequent term. Conversely, holder deputies cannot be elected as substitutes for the term immediately following their tenure. These rules aim to encourage political renewal and prevent the concentration of power.
Election of Lower Chamber Members by Relative Majority
The 300 deputies elected by relative majority are chosen in 300 single-member districts. The distribution of these districts among the thirty-two states is based on population percentage in each state. The Constitution mandates that no state can have fewer than two federal single-member districts, ensuring a minimum level of representation for even the least populated states.
Every ten years, following the national census, the distribution of these 300 districts is revised to ensure that each deputy represents a roughly equivalent segment of the population, upholding the principle of vote equity. The most recent redistricting, based on the 2000 census, was carried out between April 2004 and January 2005. This distribution was in effect until the 2009 midterm federal elections. A new redistricting was scheduled before the 2012 presidential and legislative elections, reflecting the dynamic nature of population distribution and the commitment to fair representation.
The following table illustrates the distribution of the 300 single-member districts across the thirty-two states, as revised in 2004 and applicable until the 2009 midterm elections.
| State | Districts |
|---|---|
| Aguascalientes | 3 |
| Baja California | 8 |
| Baja California Sur | 2 |
| Campeche | 2 |
| Chiapas | 12 |
| Chihuahua | 9 |
| Coahuila | 7 |
| Colima | 2 |
| Distrito Federal | 27 |
| Durango | 4 |
| State of Mexico | 40 |
| Guanajuato | 14 |
| Guerrero | 9 |
| Hidalgo | 7 |
| Jalisco | 19 |
| Michoacan | 12 |
| Morelos | 5 |
| Nayarit | 3 |
| Nuevo Leon | 12 |
| Oaxaca | 11 |
| Puebla | 16 |
| Queretaro | 4 |
| Quintana Roo | 3 |
| San Luis Potosi | 7 |
| Sinaloa | 8 |
| Sonora | 7 |
| Tabasco | 6 |
| Tamaulipas | 8 |
| Tlaxcala | 3 |
| Veracruz | 21 |
| Yucatan | 5 |
| Zacatecas | 4 |
| TOTAL | 300 |
Election of Lower Chamber Members by Proportional Representation
The 200 Lower Chamber members elected through proportional representation are chosen from regional party lists in five multi-member districts. Each of these districts elects 40 deputies. This system ensures that smaller parties and diverse political viewpoints gain representation in the Chamber.
To participate in the proportional representation election, a political party must demonstrate that it has registered candidates for the majority-rule Lower Chamber seats in at least 200 of the 300 single-member districts. Meeting this requirement allows a party to register its regional candidate lists in the five multi-member districts. These regional lists are “closed and blocked,” meaning the order of candidates is fixed and cannot be altered, and no candidate can be removed.
For a party to be eligible for proportional representation seats in the Lower Chamber, it must secure at least 2% of the total votes cast in these elections. Parties meeting this threshold, along with the district candidate registration requirement, are allocated proportional representation deputies based on their national vote percentage. This allocation is subject to the rules regarding the maximum number of seats a party can hold (300) and the 8% vote-seat proportionality rule, when applicable.
Electoral law specifies the formulas and procedures for allocating proportional representation seats, accounting for various scenarios and provisions outlined in the Constitution. This intricate system aims to balance fairness, representation, and governability.
Composition of the Upper Chamber (Senate)
The Upper Chamber, or Senate, consists of 128 members. Senators are elected through a mixed system that combines majority and proportionality principles, although these operate independently unlike in the Lower Chamber. This design is intended to provide a different form of representation, often viewed as representing the states more directly.
In each of the thirty-two states, three senators are elected. Political parties must register lists with two candidate formulas for these seats. Two of the three seats are allocated using the relative majority principle, going to the party that wins the most votes in the state. The third seat is assigned using the “first minority” principle, awarded to the party that comes in second place, ensuring some representation for the runner-up.
The remaining thirty-two Senate seats are filled through proportional representation, using national voter rolls in a single national multi-member district. The law mandates a pure proportionality formula (natural quotient and higher remainder) for allocating these seats. This national proportional representation component further enhances the diversity of representation in the Senate.
As with the Lower Chamber, substitute senators can be elected as holder senators in the subsequent term if they have not previously held office. However, holder senators cannot be elected as substitutes for the term immediately following their service, maintaining term limits and encouraging political renewal.
The Plenary Hall of the Mexican Senate, the upper house of the national legislature.
Sessions and Operations of the Mexican Congress
The Constitution sets quorum requirements for both chambers of Congress to begin sessions and exercise their powers. Neither chamber can officially convene or conduct business unless more than half of its total members are present. However, if a quorum is not initially present, the members who are present are required to meet on the legally designated day and compel absent members to attend within the following thirty days.
If absent members fail to appear within this 30-day period, they are deemed to have resigned their office, and their substitutes are summoned. Substitutes are then given 30 days to appear. Failure of substitutes to appear leads to the seats being declared vacant, triggering new elections to fill them. These rules are designed to ensure the functionality and continuity of the legislative process.
Congress holds two ordinary session periods each year. The first period commences on September 1st and can extend until December 15th of the same year. However, in years when a new President of the Republic takes office, this session period can be extended until December 31st to accommodate the transition of power. The second session period begins on February 1st and concludes on April 30th.
During congressional recess periods, a Standing Commission is formed, consisting of 37 members: 19 from the Lower Chamber and 18 from the Upper Chamber. These members are appointed by their respective chambers on the day before the adjournment of the ordinary session periods. The Standing Commission plays a crucial role in maintaining legislative oversight when Congress is not in full session.
The Standing Commission has the exclusive power to convene Congress or either chamber for extraordinary sessions. This can be done either at the Commission’s own initiative or at the request of the Executive Branch. In either case, a two-thirds vote of the members present in the Standing Commission is required to call for extraordinary sessions, ensuring that such sessions are convened only when necessary and with broad support.
The right to initiate laws or decrees is exclusively vested in the President, members of both the Upper and Lower Chambers of Congress, and state legislative bodies. This provision outlines the formal process for legislative proposals within the Mexican legal system.
It’s important to note that the federal legal system in Mexico does not recognize mechanisms of semi-direct democracy such as plebiscites, referendums, citizen’s initiatives, or the recall of elected representatives. The system relies primarily on representative democracy through elected officials and institutions.
