Complex sentence: During the 1970 gubernatorial campaign, Samuelson supported molybdenum mining in central Idaho's White Cloud Mountains, and was defeated for re-election by Andrus--a staunch opponent of the mining development--and returned to private life.
Split into simpler sentences: During the 1970 gubernatorial campaign, Samuelson came out in support of developing molybdenum mining in central Idaho's White Cloud Mountains. Samuelson was defeated for re-election by Andrus--a staunch opponent of the mining development--and returned to private life.