The killing of a legal assistant and injuries to others allegedly committed by a participant in the Charlottesville, Virginia, white supremacist rally over the weekend triggered calls for the defendant to face charges of domestic terrorism and hate crimes. But as the U.S. Supreme Court has shown, hate crime prosecutions, in particular, present difficult legal problems.

James Alex Fields Jr. of Maumee, Ohio, was denied bail in general district court in Charlottesville on Monday after being charged under state law with one count of murder, three counts of malicious wounding and one count of hit-and-run. Fields, who was taking part in the white nationalist rally, allegedly drove his car into a group of counter-protesters, killing Heather Heyer of Charlottesville and injuring 19 others.