 McCain had thought about entering politics since his return from Vietnam , although 1964 had been the only time in his life he had ever voted . In 1976 , he briefly thought of running for the U.S. House of Representatives from Florida ; he had the support of some local figures in Jacksonville , but was convinced by other Republican Party leaders that he did not have sufficient political experience , funding , or popular support to defeat longtime Democratic incumbent Charles E. Bennett . Instead , he worked so hard for Ronald Reagan 's 1976 Republican primary campaign that his base commander reprimanded him for being too politically active for his naval position . 
