Also the MSM noticed. Bump is a Washington Post reporter.
The point is that this implies that Mueller thinks Trump was guilty and that he would have a reasonable chance of convincing a jury that there is proof beyond reasonable doubt of Trump’s guilt.
The other answer was “that was a sufficient reason to not indict Trump which doesn’t imply that it was a necessary condition. As written in the report I don’t think it is fair to discuss the question of
update: in the afternoon, Mueller took it back
When he appeared before the Intelligence Committee in the afternoon, Mueller clarified this exchange, noting that it was not solely because of the Office of Legal Counsel opinion that he did not charge Trump with a crime. Instead, he said, “we did not reach a determination as to whether the president committed a crime.”
This is inconsistent with his exchange with Liu. The key word is “the” in “the reason”. Liu asserted that there was only one reason and Mueller agreed. But in any case, the bottom line is that he took it back.