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.
Plutarco Elías Calles
Under Calles's rule in 1926, a constitutional change was passed that allowed for a non-consecutive re-election, and in 1928 Obregón was elected as Calles's successor; this amendment was later repealed in 1934. In addition, Mexico passed an amendment to the constitution in 1927 that expanded a presidential term from four years to six years. However, Obregón was murdered by José de León Toral, a Catholic militant, before he could assume power. To avoid a political vacuum, Calles named himself "Jefe Máximo", the political chieftain of Mexico and Emilio Portes Gil was appointed temporary president, although in reality he was little more than a puppet of Calles. The following year, Calles founded the National Revolutionary Party (, PNR), the predecessor of today's Institutional Revolutionary Party (, PRI).