Capacious and loving First Amendment protections, though, do nothing to mitigate the failings of O’Donnell. With his repeated “if true” caveats, O’Donnell was mocking the core idea of journalism — which is to say, the verification of stray tips and rumors. Reporters and TV hosts mess up all the time, broadcasting scoops that turn out to be flimsy or just plain untrue. The mistakes stem from poor execution, misunderstandings, uncooperative subjects, stupidity, groupthink — and any number of other considerations that fall short of warranting disciplinary action. Here, the catastrophe appears to flow from one man’s conclusion that having Russian oligarchs on Trump loan documents is a story that’s too good to check. When we asked an MSNBC spokesperson whether O’Donnell did indeed check with someone in the Trump orbit before his report, we received another decline-to-comment response.

Is such a fellow fit to host an MSNBC program?