Since my posting just yesterday, which noted that the President Trump’s flouting of norms may be exposing him to legal peril, he seems unable to change course. Today brings news of a fresh and potentially grave misstep, this time accomplished by a tweet.

The President chose this medium of communication to issue a threat against someone who could be a witness in an obstruction investigation—the former Director of the FBI. He has suggested that, before embarking on any leaking activity, Mr. Comey consider carefully whether the President might have "tapes" of their conversations.

It can be granted the President is not threatening Mr. Comey to stop him from testifying in a congressional proceeding, to investigators, or to a grand jury. He is complaining about leaking. However, Mr. Trump appears not to understand that he is drawing a certain picture of himself, which is neither pretty nor without consequence for his legal position. This self-portrait can be counted on to color unfavorably any assessment of his motives when more formal inquiries into his behavior are considered or take place. While it is certainly true that prosecutors should pursue the crime and not specific individuals, suspicious behavior cannot help but draw attention to itself and push forward an investigation.

The picture that Mr. Trump has managed to create so far consists of the following:

The admission that he sought repeated assurances about his legal exposure in an ongoing criminal investigation

The pursuit of those reassurances at a time when he was quite actively holding open the possibility that Mr. Comey might not hold onto his job. (Apparently one of these conversations took place over dinner—as it was being served, was the President making it clear that Mr. Comey might have “to sing for his supper”?)

The admission that in firing Mr. Comey, he was moved decisively by his frustration over the FBI's handling of the Russia probe investigation.

The President's repeated very public statements, heard by all, including those charged with investigating the matter, that he views the Russia probe as having no merit. Responsible for the faithful execution of the laws and the integrity of the system of justice, Mr. Trump has chosen to actively dispute the basis for an ongoing FBI investigation that affects his interests.

The repeated adjustments to the story the White House originally told about the circumstances surrounding the decision to dismiss Mr. Comey. As noted in the earlier posting, it is not advantageous to somebody under suspicion to be altering his story—or, in this case, changing it in every material detail.

And now Mr. Trump has resorted to Twitter to suggest that he might have information about these conversations with the former FBI Director that the latter should worry about before deciding to disseminate his version of events. The President has drawn attention to the possibility that he has some material—some evidence—bearing on those conversations, which will certainly be of interest in any future inquiry into this dismissal. Mr. Trump’s threat to deploy these “tapes” unless Mr. Comey refrains from giving his side of the story is highly imprudent.

What is most remarkable is that the President has willingly created this self-portrait. As scandals-in-the-making go, this one may become famous for featuring the President as the principal witness against himself: he seems committed to uncovering any cover-up.