 Cárdenas managed to unite the different forces in the PRI and set the rules that allowed his party to rule unchallenged for decades to come without internal fights.He nationalized the oil industry (on 18 March 1938), the electricity industry, created the National Polytechnic Institute, and started land reform and the distribution of free textbooks to children.In 1936 he exiled Calles, the last general with dictatorial ambitions, thereby removing the army from power.