But despite these very different approaches, by the time Comey wrapped up the Clinton investigation and Mueller signed off after his report on Russian electoral interference and presidential obstruction, they ended up at much the same place: targets of immense frustration. Comey was maligned by Democrats for inflicting political injury on Clinton, then by Republicans for what they saw was his pursuit of a lawless, underhanded vendetta against Trump; and in both cases, the critique was largely that, for reasons of misguided ethical zeal or unbounded vanity, he had ignored legal limits and crashed through norms.

Mueller’s sin was often described in very much the opposite way: as the pulling of his punches, reflected in the confusing, half-in and half-out analysis of possible obstruction of justice. The New York Times editors who had praised him when appointed as “one of the few people with the experience, stature and reputation to see the job through” suggested this week that “ as the foremost expert on the president’s questionable doings, with expertise earned on the taxpayer’s dime,” he had proven too fearful that he would “endanger [his] own image by expressing a forthright view of those doings, even if the future of the Republic might be at stake.”

Neither the moral crusader nor the straight arrow have fared well, then, in the most recent tests of our processes for investigating high-level executive branch wrongdoing.