Senate of the Republic (Mexico)

Senate of the Republic (Mexico). The Senate of the Republic is the upper chamber of the bicameral Congress of the Union, the federal legislative branch of Mexico. Established by the Constitution of 1824, it serves as a body of federal representation and revision, with key roles in ratifying international treaties, approving high-level presidential appointments, and serving as a jury in political trials. Its 128 members are elected for a single six-year term, coinciding with the presidential term, through a mixed system of plurality voting and proportional representation.

History

The Senate was first constituted on October 4, 1824, following the promulgation of the Constitution of 1824 after the dissolution of the First Mexican Empire. It was abolished in 1857 under the centralist Seven Laws and later by the liberal Constitution of 1857, which established a unicameral congress. The chamber was permanently restored by the Constitution of 1917 drafted after the Mexican Revolution, which solidified its modern form. Throughout the 20th century, during the hegemony of the PRI, the Senate operated under a dominant-party system. Significant electoral reforms, such as those following the 1994–95 peso crisis, introduced proportional representation seats, increasing political pluralism.

Composition and election

The Senate is composed of 128 senators, each serving a single six-year term without the possibility of immediate re-election. Members are elected through a parallel voting system. Each of the 32 states elects three senators: two are assigned to the party receiving the largest plurality of votes, and the third is allocated to the first minority party. The remaining 32 senators are elected by a system of proportional representation from a single national constituency. This process occurs concurrently with the presidential election every six years, a period known as the *sexenio*.

Powers and functions

The Senate possesses exclusive constitutional powers distinct from the Chamber of Deputies. It ratifies international treaties and conventions signed by the President of Mexico, and approves the President's appointments, including cabinet secretaries, Supreme Court justices, attorneys general, and ambassadors. It also authorizes the deployment of Mexican troops outside national borders and the transit of foreign troops through Mexican territory. Furthermore, the Senate functions as a jury in impeachment trials against state governors and other high officials, and can declare a state governor unfit to govern, appointing a provisional governor.

Leadership and organization

The directing body of the Senate is the Board of Directors, elected for a one-year term. It is led by the President of the Senate, a position held by Ana Lilia Rivera of the Morena party for the LXV Legislature. The Board also includes a First Vice President, currently Javier Lozano Alarcón of the PAN, and a Second Vice President, Sasil de León Villard of the PVEM. Legislative work is organized into ordinary periods from September 1 to December 15 and from February 1 to April 30, with the possibility of extraordinary sessions convened by the Permanent Commission.

Committees

The substantive legislative work is conducted in permanent standing committees, where bills are debated and refined before plenary votes. Key committees include the United Nations Committee, the Justice Committee, the Public Security Committee, the Treasury Committee, and the Foreign Relations Committee. Each committee is composed of senators from different political parties proportionally to their representation in the full chamber. Special committees can also be formed to investigate specific matters, such as the committee investigating the Iguala mass kidnapping.

Current membership

The current LXV Legislature, seated in 2021, will serve until August 31, 2024. The governing coalition, led by President Andrés Manuel López Obrador's Morena party, holds a majority with its allies the PT and the PVEM. The main opposition bloc consists of the PRI, the PAN, the MC, and the PRD, which often coordinate in the opposition bench. Notable senators include former Secretary of the Interior Olga Sánchez Cordero and former Head of Government Claudia Sheinbaum. The next election for the Senate will coincide with the 2024 Mexican general election.