Ultimately federal prosecutor John Durham will have his say. He brings tools and powers that Mr. Horowitz lacks. He should be able to suss out the contribution of other U.S. intelligence agencies to the debacles here. Historians will have their say, with their special perspective on the temptations of bureaucratic self-deception and the comedy of errors that official life frequently entails (a crucial framing, we suspect, of the 2016 intelligence follies).

This might be the place to end but for the ironic coincidence of the Washington Post’s unveiling of its exposé on 18 years of official lying and confusion about the war in Afghanistan. In one sense, nothing is surprising here but raises a question: Why are we impeaching Donald Trump when the people trying to remove him are no better than he is?

Whatever his legitimate complaints about his treatment at the hands of the FBI, Mr. Trump managed to win in 2016. Hillary Clinton fans are the ones still contending that improper FBI actions cost her the election. We can only wonder when Democrats and their media supporters will find their way out of their own fog and start demanding an unsparing examination of the FBI’s role in the 2016 race.