hang (someone) in effigy
To protest someone by displaying a representation of them, such as an image or dummy, being hanged. (An "effigy" is such a representation.) In protest of the war, a large group has set about hanging the president in effigy outside the White House.
hang someone in effigy
Fig. to hang a dummy or some other figure of a hated person. They hanged the dictator in effigy. The angry mob hanged the president in effigy.