On March 18, 1938, Mexican President Lazaro Cardenas expropriated the properties of the American, English, and Dutch oil companies operating in Mexico. Was this the ideological act of a political radical? Or a calculated piece of realpolitik that united the Mexican business class with the socialist labor movement to forge the coalition that would rule Mexico for the next sixty years?Suggested reading: Jonathan C. Brown and Alan Knight, "The Mexican Petroleum Industry in the Twentieth Century."