By leaving open the question of whether Donald Trump obstructed justice, Robert Mueller fairly begs Congress to pursue it. We may or may not learn from the full text of Mueller’s report why he chose neither to charge Trump nor to exonerate him. It would be useful to know, but either way the duty now falls to Congress.

The Constitution states that a president can prosecuted for crimes after he leaves office, but uses impeachment as the sole remedy while the president is in office. Hamilton, in three separate entries in the Federalist Papers, Numbers 65, 69, and 77, defined the nature and purposes of impeachment.

In Federalist No. 77, he wrote that impeachable offenses were “those offences which proceed from the misconduct of public men, or in other words from the abuse or violation of some public trust”. That surely describes the Trump presidency.

The Constitution makes no mention of a special prosecutor or of criminal prosecution while a president is in office. So the remedy, and Congress’s duty, are unmistakable—a full investigation and if warranted, an impeachment.

And even that doesn’t quite get Trump or his family off the hook for criminal prosecutions. The nature of the Trump organization, as a criminal enterprise, was not within Mueller’s remit except to the extent that it corrupted his presidency. But several prosecutors are still on that case.

Trump has had a good weekend. He still looks to have a bad year.