Trump is driving white nationalism. Biden needs to say so.

In a commencement address delivered at Howard University in Washington, D.C., on Saturday, President Joe Biden correctly deemed white supremacy “the most dangerous terrorist threat to our homeland.” He was quick to add that he wasn’t saying this just because he was speaking at a historically Black university. “I say it wherever I go,” he added.

Biden is right to highlight the threat from violent white supremacists, who federal law enforcement agencies say “promote accelerationist thinking, which advocates committing violence to precipitate a large-scale conflict often framed as a race war” in order to establish a “white...