After initially endorsing Percy Sutton in the 1977 mayoral election , he subsequently endorsed Ed Koch over Mario Cuomo in the Democratic primary run - off .
Besides his increasing influence in Washington , by the late 1970s Rangel was New York City 's leading black political figure .
After initially endorsing Percy Sutton in the 1977 mayoral election , Rangel subsequently endorsed Ed Koch over Mario Cuomo in the Democratic primary run - off .
Besides his increasing influence in Washington , by the late 1970s Rangel was New York City 's leading black political figure .