Vicente Lombardo Toledano was one of the foremost Mexican labor leaders of the 20th century, called "the dean of Mexican Marxism [and] the best-known link between Mexico and the international world of Marxism and socialism." In 1936, he founded the Confederation of Mexican Workers (CTM), the national labor federation most closely associated with the ruling party founded by President Lázaro Cárdenas, the Party of the Mexican Revolution (PRM). After he was purged from the union after World War II, Lombardo Toledano co-founded the political party "Partido Popular" along with Narciso Bassols, which later became known as the Partido Popular Socialista.

Lázaro Cárdenas del Río was a Mexican army officer and politician who served as president of Mexico from 1934 to 1940. Previously, he served as a general in the Constitutional Army during the Mexican Revolution and as Governor of Michoacán and President of the Institutional Revolutionary Party. He later served as the Secretary of National Defence. During his presidency, which is considered the end of the Maximato, he implemented massive land reform programs, led the expropriation of the country's oil industry, and implemented many left-leaning reforms.