Most people haven't read the report and have relied on summaries in the news media or from Attorney-General William Barr to guide their understanding of it.
Barr's position was clear from the first four-page letter he offered publicly. Mueller didn't find a chargeable conspiracy by members of the Trump campaign to work with the Russian Government to influence the 2016 presidential campaign and, by his own assessment, the potentially obstructive acts that Donald Trump undertook weren't criminal. In his news conference before the report was released, Barr stated flatly that "no collusion" had taken place.
Each of those assertions was celebrated by Barr's boss, US President Donald Trump. Trump summarised Mueller's findings in an inaccurate four-word statement: No collusion, no obstruction. But each of Barr's assertions also diverged from what the report said.
What Mueller did today was essentially hold up the report and point at it, telling America what it contained. By doing so, we have for the first time heard a member of the executive branch convey the report's findings accurately - in a way that Americans and the media would be hard-pressed to misinterpret.
Mueller noted that his team indicted more than two dozen Russians in connection with their alleged roles in hacking Democratic networks and accounts and with trying to interfere in the campaign via social media.
But instead of saying that there was "no collusion" by the Trump team with that effort - a term that the report itself explicitly rejected in its consideration of what happened - Mueller explained what his investigators found in more nuanced terms.
The first volume of his report, he said, "includes a discussion of the Trump campaign's response to this activity as well as our conclusion that there was insufficient evidence to charge a broader conspiracy."
Insufficient evidence, of course, is not a lack of evidence.
Again, this distinction exists within the report, but it's not how Trump or Barr presented Mueller's findings.
The second volume of the report assesses Trump's efforts to undermine Mueller's investigation. Here, Mueller spoke at length.
"Under long-standing department policy, a president cannot be charged with a federal crime while he is in office," Mueller said. "That is unconstitutional, even if the charge is kept under seal and hidden from public view. That, too, is prohibited. The special counsel's office is part of the Department of Justice, and by regulation it was bound by that department policy."
"Charging the President with a crime," he continued, "was therefore not an option we could consider."
This conflicts with what Barr said at that news conference before the report was released publicly. The Attorney-General was asked whether the opinion from the Justice Department's Office of Legal Counsel (referred to by Mueller above) was the reason Mueller didn't charge Trump with a crime.
"He - he was not saying that but for the OLC opinion he would have found a crime," Barr said. "He made it clear that he had not made the determination that there was a crime."
Because of the boundaries established by that opinion, Mueller said today, "we concluded that we not reach a determination one way or the other about whether the President committed a crime."
In fact, the report says, his team would have exonerated Trump on obstruction charges if it could.
It couldn't.
Mueller, in his statement today, explained how the OLC opinion guided their work. First, he said, the opinion allows for an investigation of a sitting president in order to preserve evidence. Second, it points to the existence of other mechanisms for accusing sitting presidents of crimes.
It's easy to read between the lines here, though Mueller was still not direct.
Among the other mechanisms are, of course, impeachment. Mueller noted that preserving evidence could be useful to charge co-conspirators "among other things". An impeachment trial is, in fact, another thing.
For two months, the Special Counsel has seen others, Barr and Trump included, try to frame his work in a particular way.
He pointedly stated that he didn't question Barr's "good faith" in releasing the full report, begging the question of points at which his confidence in Barr's efforts was less robust. He apparently hoped that the release of the report would stand in contrast to the Barr-Trump framing (as was made clear in his letter to Barr), but that wasn't borne out.
So, for the first time since he was appointed in May 2017, he decided to speak directly. In so doing, he was able to do what no one else from the Trump Administration had yet done: Capture the public attention and use the moment to accurately and briefly convey what his investigation found and what his report said.
"It is important that the office's written work speak for itself," Mueller said. It was a warning that applied to his own comments - but also, obviously, those of his superiors.
