1972 was the beginning of “four more years”
I guess in 1968 no one was wanting 4 more years of LBJ including Lyndon and JFK didn’t get a shot a 4 more years in 64.
If it does go back further than that it would be either IlikeIKE in 1956, HarryStruman in 1948 or one of the 3 times FDR was running for re-anointment