The attorney general essentially argued that if a president really, really, really believes he is innocent of a crime, then he can undermine an investigation of that crime without the “corrupt motive” required to prove obstruction of justice. Said Barr: “If the president is being falsely accused — which the evidence now suggests that the accusations against him were false — and he knew they were false, and he felt that this investigation was unfair, propelled by his political opponents, and was hampering his ability to govern, that is not a corrupt motive for replacing an independent counsel.”

This is a remarkable claim on several counts. The Mueller report does not provide evidence that the accusations against Trump were false. It found that the evidence was not sufficient to prove a criminal conspiracy. If the accusation is that the Trump campaign had extensive, disturbing contacts with a hostile foreign power in an attempt to gain political advantage, then the Mueller report comprehensively proves the charge. This tendency by Barr to equate the absence of a crime with vindication for the president is what makes him sound like part of Trump’s defense team. It is also what seems to have rubbed special counsel Robert S. Mueller III the wrong way, provoking his “snitty” letter of protest to Barr.

It is the broader implications of Barr’s view of obstruction, however, that should concern us the most. He is claiming that Trump’s belief in his own innocence, along with his conviction that political opponents were out to get him, constituted a sufficiently pure motive to fire Mueller (and much else) without incurring the guilt of obstruction of justice. But what president — Richard M. Nixon included — does not believe in his own innocence until a smoking gun appears? What president does not believe that his opponents are unfairly accusing him? And how should an attorney general determine that such beliefs are sincerely held?