Even those who have long since accepted the premise that Donald Trump is corrupt, self-centered and dishonest seem a bit shocked by his tirades over the Presidents’ Day weekend. Using the Parkland, Fla., massacre as an excuse to attack the F.B.I. for investigating Russian election intervention on his behalf — while lying about his own past denials that such intervention took place — took vileness to a new level, which is truly impressive given Trump’s previous record.

Yet if you step back a bit and think about it, Trump’s latest outbursts were very much in character — and I don’t just mean his personal character. When did you last see a member of the Trump administration, or for that matter any prominent Republican, admit error or accept responsibility for problems?

Don’t say that it has always been that way, that it’s just the way people are. On the contrary, taking responsibility for your actions — what my parents called being a mensch — used to be considered an essential virtue in politicians and adults in general. And in this as in so many things, there’s a huge asymmetry between the parties. Of course not all Democrats are honest and upstanding; but as far as I can tell, there’s almost nobody left in the G.O.P. willing to take responsibility for, well, anything.

And I don’t think this is an accident. The sad content of modern Republican character is a symptom of the corruption and hypocrisy that has afflicted half of our body politic — a sickness of the soul that manifests itself in personal behavior as well as policy.