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.
Mexican Democratic Party
Whilst the UNS faded after the 1940s it continued as a local group and was boosted, along with a number of other opposition groups, by a series of electoral reforms during the 1970s that introduced an element of proportional representation into the electoral system. As a result of these the UNS, the activities of which were largely confined to Guanajuato, reconstituted as a political party under the name Mexican Democratic Party. The party was formed against a backdrop of renewed importance for the Catholic Church in Mexican society, with a growth in the influence of groups such as Opus Dei whilst the opposition National Action Party (PAN) self-identified as Catholic. The two parties differed however in that the PDM drew support from peasants whilst the PAN was firmly the province of the urban middle classes.