On March 24, attorney general William Barr released a four-page letter declaring that the evidence compiled by special counsel Robert Mueller was "not sufficient" to establish Donald Trump's criminality. It was a difficult claim to evaluate, for two reasons: First, because the Department of Justice had not yet released Mueller's report, there was no way for anyone to verify or interrogate Barr's assertions. And second, both before his nomination and then during his confirmation hearings, Barr more or less promised that if he were confirmed to that office, he would conclude that the president had not obstructed justice.

As it turns out, among the many observers who harbored concerns about the thrust of Barr's letter was Robert Mueller himself. On March 25, the day after Barr released his summary, Mueller wrote the first of at least two letters to Barr in which he stated that Barr's document "did not fully capture the context, nature, and substance of [the special counsel's office's] work and conclusions." This result, Mueller explained, "threatens to undermine a central purpose" of the probe: to assure "full public confidence" in its outcome. The special counsel's letter reads as polite, but in the world of stilted, performative collegiality that lawyers inhabit, this qualifies as vehement disagreement with his colleague's choice.

On Tuesday evening, hours before Barr was scheduled to testify before the Senate Judiciary Committee, the Washington Post reported that in a follow-up phone call on March 28, Mueller reiterated to Barr his concern that "media coverage of the obstruction investigation was misguided and creating public misunderstandings about the office’s work." To clear up the uncertainty created by the attorney general, Mueller asked the him to release an executive summary, excerpted from the report, which the special counsel's office specifically prepared for public consumption. And on at least two separate occasions, Barr refused to do so.

According to the Post, he explained to Mueller that he "did not want to put out pieces of the report, but rather issue the document all at once with redactions," and "didn't want to change course." These exchanges are notable because on several occasions over the past month, when members of Congress asked Barr about media reports that Mueller had privately disputed Barr's public conclusions, Barr has testified under oath that he had no earthly idea what anyone was talking about.