The legislative branch of the Mexican government consists of a bicameral congress (Congreso de la Unión) divided into an upper chamber, or Senate (Cámara de Senadores), and a lower chamber, or Chamber of Deputies (Cámara de Diputados). As in the United States, both chambers are responsible for the discussion and approval of legislation and the ratification of high-level presidential appointments. In theory, the power of introducing bills is shared with the executive, although in practice the executive initiates about 90 percent of all legislation.
The congress holds two ordinary sessions per year. The first session begins on November 1 and continues until no later than December 31; the second session begins on April 15 and may continue until July 15. A Permanent Committee (Comisión Permanente), consisting of thirty-seven members (eighteen senators and nineteen deputies), assumes legislative responsibilities during congressional recesses. The president may call for extraordinary sessions of congress to deal with important legislation.
Historically, the Senate consisted of sixty-four members, two members for each state and two representing the Federal District elected by direct vote for six-year terms. However, as part of the electoral reforms enacted by the Salinas government in 1993, the Senate was doubled in size to 128 members, with one of each state's four seats going to whichever party comes in second in that state. Since 1986 the Chamber of Deputies has consisted of 500 members, 200 of whom are elected by proportional representation from among large plurinominal districts, and the remainder from single-member districts. Members of the Chamber of Deputies serve three-year terms. All members of the congress are barred from immediate reelection but may serve nonconsecutive terms.
The powers of the congress include the right to pass laws, impose taxes, declare war, approve the national budget, approve or reject treaties and conventions made with foreign countries, and ratify diplomatic appointments. The Senate addresses all matters concerning foreign policy, approves international agreements, and confirms presidential appointments. The Chamber of Deputies, much like the United States House of Representatives, addresses all matters pertaining to the government's budget and public expenditures. As in the United States, in cases of impeachment, the Chamber of Deputies has the power to prosecute, and the Senate acts as the jury. In some instances, both chambers share certain powers, such as establishing committees to discuss particular government issues and question government officials. The deputies have the power to appoint a provisional president. In the event of impeachment, the two chambers are convened jointly as a General Congress. Each legislative chamber has a number of committees that study and recommend bills. If there is disagreement between the chambers, a joint committee is appointed to draft a compromise version.
The judicial branch of the Mexican government is divided into federal and state systems. Mexico's highest court is the Supreme Court of Justice, located in Mexico City. It consists of twenty-one magistrates and five auxiliary judges, all appointed by the president and confirmed by the Senate or the Permanent Committee.
Mexican supreme court justices must be Mexican citizens by birth, thirty-five to sixty-five years old, and must have resided in Mexico and held a law degree during the five years preceding their nomination. According to the constitution, supreme court justices are appointed for life but are subject to impeachment by the Chamber of Deputies. In practice, the justices, along with the entire federal judiciary, traditionally submit their resignations at the beginning of each sexenio
The Supreme Court of Justice may meet in joint session or in separate chambers, depending on the type of case before it. The high court is divided into four chambers, each with five justices. These are the Penal Affairs Chamber, Administrative Affairs Chamber, Civil Affairs Chamber, and Labor Affairs Chamber. A fifth chamber, the Auxiliary Chamber, is responsible for the overload of the four regular chambers. Court rulings of both the whole, or plenary, court and the separate chambers are decided on the basis of majority opinion. Rulings by the separate chambers may be overturned by the full court.
There are three levels of federal courts under the Supreme Court of Justice: twelve Collegiate Circuit Courts, each with three magistrates; nine Unitary Circuit Courts, each with six magistrates; and sixty-eight District Courts, each with one judge. Federal judges for the lower courts are appointed by the Supreme Court of Justice. The Collegiate Circuit Courts are comparable to the United States Courts of Appeals. The Collegiate Circuit Courts deal with the protection of individual rights, most commonly hearing cases where an individual seeks a writ of amparo
, a category of legal protection comparable to a broad form of habeas corpus that safeguards individual civil liberties and property rights. The Unitary Circuit Courts also handle appeals cases. The Collegiate Circuit Courts are located in Mexico City, Toluca, Guadalajara, Monterrey, Hermosillo, Puebla, Veracruz, Torreón, San Luis Potosí, Villahermosa, Morelia, and Mazatlán. The Unitary Circuit Courts are located in Mexico City, Toluca, Guadalajara, Monterrey, Hermosillo, Puebla, Mérida, Torreón, and Mazatlán.
The Mexican legal system is based on Spanish civil law with some influence of the common law tradition. Unlike the United States version of the common law system, under which the judiciary enjoys broad powers of jurisprudence, Spanish civil law is based upon strict adherence to legal codes and minimal jurisprudence. The most powerful juridical instrument is the writ of amparo
, which can be invoked against acts by any government official, including the president. Unlike the United States system, where courts may rule on basic constitutional matters, the Mexican Supreme Court of Justice is prohibited by the constitution from applying its rulings beyond any individual case. Within this restricted sphere, the Supreme Court of Justice generally displays greater independence in relation to the president than does the legislature, often deciding against the executive in amparo
cases. Nevertheless, the judiciary seldom attempts to thwart the will of the president on major issues.
Data as of June 1996