Congress of the Union

Congress of the Union
Alex Covarrubias · Public domain · source
Name	Congress of the Union
Legislature	LXV Legislature of the Mexican Congress
House type	Bicameral
Houses	Senate, Chamber of Deputies
Foundation	28 September 1824
Preceded by	Constituent Congress of 1824
Leader1 type	President of the, Senate
Leader1	Ana Lilia Rivera
Election1	1 September 2023
Leader2 type	President of the, Chamber of Deputies
Leader2	Marcela Guerra Castillo
Election2	1 September 2024
Members	628, 128 Senators, 500 Deputies
Meeting place	Senate: Senate Building, Mexico City
Meeting place2	Deputies: San Lázaro Legislative Palace, Mexico City
Website	http://www.senado.gob.mx/, http://www.diputados.gob.mx/

Congress of the Union. The federal legislative branch of the United Mexican States, it is a bicameral body established by the Political Constitution of the United Mexican States. Its origins trace back to the early 19th century following the Mexican War of Independence, with its modern form solidified after the Mexican Revolution. The Congress convenes in Mexico City, occupying the San Lázaro Legislative Palace and the Senate Building, and serves as the central forum for national political debate, lawmaking, and oversight of the Federal government of Mexico.

History

The inaugural session was held in 1824 after the dissolution of the First Mexican Empire and the drafting of the Constitution of 1824, which created a bicameral legislature. Its functioning was disrupted by periods of instability, including the Centralist Republic of Mexico, the Mexican–American War, and the Second French intervention in Mexico. The Porfiriato era saw a largely subservient legislature until the outbreak of the Mexican Revolution. The current framework was established by the Constitution of 1917, drafted by the Constituent Congress of 1917 during the presidency of Venustiano Carranza. Subsequent political evolution, including the PRI hegemony and the transition to multiparty democracy in the late 20th century, fundamentally shaped its contemporary role.

Structure and composition

It comprises two chambers: the upper Senate and the lower Chamber of Deputies. The Senate has 128 members, with each of the 31 states and the Federal District electing three senators through a mix of first-past-the-post and proportional representation for a six-year term coinciding with the presidential term. The Chamber of Deputies has 500 members, with 300 elected from single-member districts and 200 through proportional representation from five regional plurinominal circumscriptions, serving three-year terms. Elections are administered by the National Electoral Institute.

Powers and functions

Its constitutional powers include the exclusive authority to levy federal taxes, declare war, approve the national budget drafted by the Secretariat of Finance, and ratify international treaties signed by the President of Mexico. It holds the power to admit new states to the federation, as with the 1974 elevation of Baja California Sur and Quintana Roo. The Senate has specific powers to approve presidential appointments to key posts like Supreme Court justices and ambassadors, and to authorize the use of armed forces outside national territory. Both chambers can issue declarations and form special investigative committees.

Legislative process

The process for federal laws typically begins with a bill introduced by the President of Mexico, a senator, a deputy, or a state legislature. Bills can originate in either chamber, except those concerning loans, taxes, or military recruitment, which must start in the Chamber of Deputies. A bill must be approved by a simple majority in both chambers and is then sent to the Executive for promulgation or veto. A presidential veto can be overridden by a two-thirds vote in each chamber. The internal regulations of each chamber, overseen by their respective Governing Boards, dictate the committee review and floor debate stages.

Relationship with the executive

This relationship is defined by the Constitution of 1917's principle of divided powers. The Congress exercises oversight through the right to summon cabinet secretaries like those from the Secretariat of the Interior for questioning, and to approve the annual Federal Budget of Mexico. The Chamber of Deputies has the sole power to approve the federal budget, while the Senate ratifies diplomatic appointments. A historically powerful presidency, particularly under the PRI, has given way to a more assertive legislature since the opposition victory in the 1997 midterms and the end of unified government.

Current membership and leadership

The LXV Legislature of the Mexican Congress, serving from 2024 to 2027, reflects a plural composition. The ruling coalition, led by the MORENA party of President Andrés Manuel López Obrador, holds a majority in both chambers alongside allies like the Labor Party and the Ecologist Green Party of Mexico. The main opposition bloc includes the PRI, the PAN, and the PRD. The current President of the Senate is Ana Lilia Rivera of MORENA, while the President of the Chamber of Deputies Board is Marcela Guerra Castillo of the PRI, a position that rotates among parliamentary groups. Key committee leadership, such as the Justice Committee and the Budget Committee, is distributed among the major parties.