The weightiest immediate question raised by the Jan. 6, 2021, storming of the U.S. Capitol and the continuing House hearings is whether the deadly insurrection requires an unprecedented criminal prosecution of a former president. It’s not a question anymore. The disturbing firsthand account of Cassidy Hutchinson, a former aide to White House chief of staff Mark Meadows who testified before the Jan. 6 committee in a hastily added hearing Tuesday, left Donald Trump inextricably bound to the deadly violence of that day. Hutchinson ensured as much by displaying the courage and candor many of the f...