He then attempted to mediate between Mayor Koch and some minority groups who thought the Koch administration racially insensitive .
After initially endorsing Percy Sutton in the 1977 mayoral election , he subsequently endorsed Ed Koch over Mario Cuomo in the Democratic primary run - off .
He then attempted to mediate between Ed Koch Ed Koch and some minority groups who thought the Ed Koch administration racially insensitive .
After initially endorsing Percy Sutton in the 1977 mayoral election , he subsequently endorsed Ed Koch over Mario Cuomo in the Democratic primary run - off .