Government: Constitution of 1917 in force in 1997. Formally a federal republic, although federal government dominates governments of thirty-one states and Federal District. Central government power concentrated in president, who directs activities of numerous agencies and state-owned business enterprises. Bicameral legislature (128-member Senate and 500-member Chamber of Deputies) comparatively weak. Federal judiciary headed by Supreme Court of Justice. State governments headed by elected governors; all states have unicameral legislatures; state courts subordinate to federal courts. Federal District governed by mayor (regente) indirectly elected by legislative body of the Federal District beginning in 1996; more than 2,000 local governments headed by elected municipal presidents and municipal councils.

Politics: Authoritarian system governed by president, who cannot be reelected to another six-year term. Major political organization Institutional Revolutionary Party (Partido Revolucionario Institucional--PRI), which incorporates peasant groups, labor unions, and many middle-class organizations within its ranks. Many opposition parties have had limited electoral success; largest is the conservative Party of National Action (Partido de Acción Nacional--PAN). Direct elections at regular intervals; rule of no reelection applies to most offices. Election by majority vote, except for 200 seats in Chamber of Deputies reserved for opposition parties chosen by proportional representation. considerable participation by interest groups and labor unions in government and PRI affairs.

Foreign Relations: Major attention devoted to United States. Trade and immigration along shared border subjects of continuing negotiations. Foreign policy traditionally based on international law; nonintervention the major principle. Widely active in hemispheric affairs, including good relations with Cuba.

International Agreements and Memberships: Party to Inter-American Treaty of Reciprocal Assistance (Rio Treaty). Membership in international organizations includes Organization of American States and its specialized agencies, United Nations and its specialized agencies, Latin American Alliance for Economic Development, and Latin American Economic System. Joined NAFTA in 1993.