One argument I still hear every once in awhile about keeping Clay Helton is that he won a Rose Bowl and Pac-12 title.
Well, in 1950, USC coach Jeff Cravath was forced to resign after going 2-5-2. Cravath had four won Pacific Coast Conference titles and went to four Rose Bowls.
But he still got fired after that bad season in 1950. And one of his two victories was over Notre Dame. So Helton could have been fired after a bad 2018 season.