“But he fights.” He is a litigious man who has openly boasted of using losing lawsuits to harm his critics. Yes, a president needs some combative spirit, but it should be discerning—especially when aimed at fellow Americans—and give way in due season to a spirit of reconciliation.

We don’t know when the next crisis will come. It might be a close election in which Mr. Trump needs to accept the decision of the judiciary. We might need national unity. Instead, this man’s tweets are the ground glass in the national milkshake.

A high degree of social trust is needed both for a dynamic economy and for the rule of law. But as legal scholar Orin Kerr puts it, “the president’s signature move is to attack the legitimacy of everyone and every institution who is not in lockstep with him.”

Some offer the “Flight 93 election” theory, in which every four years we face a last-chance, bet-the-country abyss. I don’t buy it. Our country has a system of rotation in office. The other party gets its turn, and the country survives. It will survive Donald Trump, too. But the country should not have to face four more years of him.