The Partido Revolucionario Institucional (PRI) is a political party in Mexico, founded in 1929. It played a dominant role in Mexican politics for much of the 20th century, promoting policies of economic development and social welfare. The PRI was known for its centralized control and was often associated with the concept of "Mexican nationalism." In the late 20th century, the PRI faced increasing competition and criticism, leading to significant electoral reforms. The party lost the presidency in 2000, marking the end of its 71-year rule. Since then, the PRI has continued to adapt to Mexico's evolving political landscape, participating in various elections and coalitions.