DAVID MCCULLOUGH GOES FULL GINSBURG: Scholars Steeped in Dead Politicians Take On a Live One: Donald Trump.

Authoritative and measured, Mr. McCullough typically strikes a tone of determined neutrality. In public appearances, he said, he deliberately avoids commentary on contemporary politics.

“Very often, during question-and-answer sessions, people ask me some question about the president or other would-be candidates,” he said in an interview this week. “I’ve always said, ‘My specialty is dead politicians.’ In that way, I could sidestep the question without getting myself involved.

“But this time around, I don’t feel that way any more.”

Now Mr. McCullough and Ken Burns, the filmmaker and author, have assembled a group of distinguished American historians to speak about the candidacy of Donald J. Trump, the presumptive Republican presidential nominee, in videos being posted to a Facebook page, Historians on Donald Trump.

Seems panicky to me.