We should be suspicious of weird coincidences. It’s week five of the Justice Department’s most high-profile—and high-stakes—criminal trial related to the events of January 6, 2021. Five members of the Proud Boys face the rare “seditious conspiracy” charge. Guilty verdicts—almost certain given the government’s near-perfect conviction rate for January 6 defendants—would build legal momentum for a similar indictment against Donald Trump. (The trial is so crucial that Matthew Graves, the Biden-appointed U.S. attorney for the District of Columbia responsible for prosecuting every January 6 case, has shown up in the courtroom on at least three occasions.) Trump is a major...