The Partido Revolucionario Institucional (PRI; Spanish for Institutional Revolutionary Party) held power in Mexico for roughly 70 years. It was the final result of all the political accommodations after the Mexican Revolution, in which most of the supporting parties finally agreed to join under its umbrella.
The party, under its different names, held every major political position during this time. Only the odd federal deputy (diputado) or senator (senador) from other parties ever got elected, and the first state governor not to come from its ranks was not elected until 1990.
The party has acquired a reputation for dishonesty to the extent that it is an open secret, and while this is admitted (to a degree) by some of its affiliates, its supporters maintain that the role of the party was crucial in the modernization of Mexico.
Perhaps Mexico's only popular 20th-century president Lázaro Cárdenas, most renowned for expropriating the oil interests of U.S. and European petroleum companies in the run-up to WW2, came from its ranks. He was a person of leftist ideas who nationalized different industries and provided many social institutions dear to the Mexican people. At the other end of the spectrum Carlos Salinas de Gortari privatized many industries, including banks and roads, and also negotiated NAFTA.
The PRI was heavily criticized for using the Mexican flag colors in its logo (something considered not unreasonable in many countries, such as the United States, but frowned upon in Mexico). This is expressely forbidden by the law, but was flaunted with many excuses, the most amusing being that the colours were transparent but the background behind was that of the Mexican flag.
In recent years the following have been key events in the history of the PRI: