Mr. Trump always hits back at critics, and Mr. Scarborough has called the President mentally ill, among other things. But suggesting that the talk-show host is implicated in the woman’s death isn’t political hardball. It’s a smear. Mr. Trump rightly denounces the lies spread about him in the Steele dossier, yet here he is trafficking in the same sort of trash.

Rep. Adam Kinzinger, a Republican from Illinois, had it right when he tweeted on the weekend: “Completely unfounded conspiracy. Just stop. Stop spreading it, stop creating paranoia. It will destroy us.”

We don’t write this with any expectation that Mr. Trump will stop. Perhaps he even thinks this helps him politically, though we can’t imagine how. But Mr. Trump is debasing his office, and he’s hurting the country in doing so.