Who's violating norms these days?

Norms, we are told, matter. Violating norms, recklessly disregarding norms — these are charges on which President Trump is often arraigned in the court of public opinion.

The indictment starts with his annoying habit of inventing insulting nicknames for his opponents and critics. You can add to the list as you will and perhaps come up with enough material just there to consume the 700-plus word limit of a newspaper column.

But Trump hasn’t been the only one disregarding norms of late. Consider the question of whether and when the...