Complex sentence: Yet Pérez's credentials as a nationalist leader were not soiled, in fact for many they were enhanced, because in 1975 he nationalized the iron industry and in 1976 he jumped further and nationalized the oil industry.
Split into simpler sentences: Yet Pérez's credentials as a nationalist leader were not soiled. In fact, for many they were enhanced because in 1975 he nationalized the iron industry, and in 1976 he jumped further and nationalized the oil industry.