Institutional Revolutionary Party
The Institutional Revolutionary Party (, PRI) is a Mexican political party founded in 1929 that held uninterrupted power in the country for 71 years from 1929 to 2000, first as the National Revolutionary Party (, PNR), then as the Party of the Mexican Revolution (, PRM), and finally renaming itself as the Institutional Revolutionary Party in 1946.
L Legislature of the Mexican Congress
Legal reform, known formally as the "Ley de Organizaciones Políticas y Procedimientos Electorales (LOPPE)" (Law of Political Organizations and Electoral Procedures), defined and made possible procedures for the registration of new political parties (in 1977 legally there were only the PRI, the National Action Party) (PAN), the Popular Socialist Party (PPS) and the Authentic Party of the Mexican Revolution (PARM)). This allowed for the registration, for the first time in 40 years of the Mexican Communist Party, which was followed by the National Assembly of the Socialist Left, the Mexican Democratic Party and the Social Democratic Party.