He did not accuse the president of a crime. But Mr. Mueller seemed to hint that he might have if he could have and pointedly refused to exonerate Mr. Trump. Likewise, he implied that Congress could pursue impeachment without directly recommending it.

“The Sergeant Joe Friday ‘just the facts’ approach will leave us with a political Rorschach test of sorts,” said Julian Epstein, who was the chief counsel to House Judiciary Committee Democrats during President Bill Clinton’s impeachment. Each side saw what it wanted to. “So it seems to me that the Mueller press conference doesn’t change the status quo a bit.”

As Mr. Epstein and even some of those appearing on Fox News pointed out, the special counsel effectively refuted Mr. Trump’s no-collusion, no-obstruction mantra. While repeating that he found no illegal coordination between Mr. Trump and Russia, Mr. Mueller clearly left the impression that he saw serious wrongdoing by the president in his attempts to thwart the investigation.