Mueller also pointed to the OLC’s guidance on seeking sealed indictments, which could be unsealed when a president leaves office, or leveling such charges in an internal (and, presumably, nonpublic) report. Secrecy, the OLC counseled, would be difficult to preserve—and so either step could place a president back in the same unfair situation, accused of a crime without the chance to clear his name.

Crucially, the same concerns don’t operate in reverse. If—examining the evidence and the law—a prosecutor were to determine not to charge an individual, there would be no fear that public disclosure of that decision would be unfair. But if Mueller believed he could not fairly say that the president had committed a crime, he also believed he could not honestly say that he hadn’t. “If we had confidence after a thorough investigation of the facts that the President clearly did not commit obstruction of justice, we would so state,” the report explained:

Based on the facts and the applicable legal standards, however, we are unable to reach that judgment. The evidence we obtained about the President’s actions and intent presents difficult issues that prevent us from conclusively determining that no criminal conduct occurred. Accordingly, while this report does not conclude that the President committed a crime, it also does not exonerate him.

Attorney General William Barr reviewed the same evidence, though, and came to a different conclusion. In his summary of the report, he wrote, “Deputy Attorney General Rod Rosenstein and I have concluded that the evidence developed during the Special Counsel’s investigation is not sufficient to establish that the President committed an obstruction-of-justice offense.”

Read: 14 must-read moments from the Mueller report

There is a vital distinction here between the two findings. Mueller wrote that his evidence was not sufficient to clearly establish that the president had not committed a crime; Barr insisted that it was not sufficient to establish that he had. It’s possible to read the two conclusions as different ways of stating the same finding; it’s equally possible to read them as fundamentally at odds with each other.

This points back to Mueller’s basic concern about fairness. In the report, he laid out 10 specific incidents his team examined, each of which might constitute—singly or in aggregate—evidence of obstructive conduct on the part of the president. “The Special Counsel’s decision to describe the facts of his obstruction investigation without reaching any legal conclusions leaves it to the Attorney General to determine whether the conduct described in the report constitutes a crime,” Barr wrote.

But there is another, simpler way to understand Mueller’s report. A footnote spells out that a criminal investigation could ultimately result in charges being brought either after a president has been removed from office by the process of impeachment or after he has left office. Mueller explicitly rejected the argument of Trump’s lawyers that a president could not be guilty of obstruction of justice for the conduct in question: “The protection of the criminal justice system from corrupt acts by any person—including the President—accords with the fundamental principle of our government that ‘[n]o [person] in this country is so high that he is above the law.’”