One of the recurring features of the Trump years has been the president’s knack for detonating so many of our powerful shared experiences into us-versus-them grenades. Whether it’s the anniversary of a national catastrophe like the Oklahoma City bombing, the death of a widely admired statesman (Senator John McCain) or a lethal pathogen, Mr. Trump has exhibited minimal interest in the tradition of national strife placing a pause upon the usual smallness of politics.

In this fractured political environment, the president has shown particular zest for identifying symbols that reveal and exacerbate cultural divisions. Kneeling football players, plastic straws and the question of whether a commander in chief should be trumpeting an untested antimalarial drug from the White House briefing room have all become fast identifiers of what team you’re on. Looming sickness and mass death are no exception. The reflex to unite during a period of collective grief feels like another casualty of the current moment…

“The coronavirus could have been Donald Trump’s finest hour,” Mr. Widmer said. “You really sensed that Americans wanted to be brought together. But now that appears unattainable.”

For whatever reason, Mr. Trump seems uninterested in setting aside personal resentment, even when some small gestures — a photo op or a joint statement with Democratic leaders in Congress; a bipartisan pandemic commission chaired by former presidents — could score him easy statesmanship points.