Every gas station in Mexico is stamped with the green-and-white logo of the state-owned oil monopoly, the economic lifeblood of the government. Oil Expropriation Day, commemorating the day Mexico seized control of the industry from foreign companies in 1938, is celebrated with speeches and even parades in some towns. An old song, “The Oil Worker Hymn,” credits oil with “saving our fatherland.” But now, in what could be the biggest economic change in two decades, President Enrique Peña Nieto is on the verge of rewriting the Constitution to open Mexico’s oil, gas and electricity industry to private investment — a provocative move expected to lure international oil companies and expand North America’s energy supply while testing the grip oil has on Mexico’s soul. “We must defend our oil,” Cuauhtémoc Cárdenas, a three-time presidential candidate and son of the president who nationalized the oil industry, […]