Robert Mueller is an honorable man, as Marc Antony might have put it. And in his public statement Wednesday we saw a special counsel who went out of his way not to absolve Donald Trump and may have put his thumb on the scale toward impeachment.

Mr. Mueller offered no new facts about his probe at a press appearance in which he read a statement and took no questions. The event was mainly intended to deflect bipartisan requests that he testify on Capitol Hill about his 448-page report on Russia and the Trump campaign. He may...