It would be a dull quest, but a difficult one, to find a 70-something white male conservative less like President Donald Trump than Chief Justice John Roberts. Mr Roberts is mild where the other is bombastic, endowed with impeccable establishment credentials where the other has credentialled himself, obsessed with consensus and continuity, not disruption. The chief justice never tweets; he has attained just one wife. And yet, as Mr Trump has been building a movement to remake America to suit himself, Mr Roberts, like the stewards of so many American institutions, has been failing at his job, at least by the standards he set when he became the chief 20 years ago.