By Benedict Carey and Jan Hoffman

What if Billy Bush had just changed the subject?As unlikely as that may sound to anyone who has heard the infamous 2005 tape of Donald J. Trump boasting about sexually accosting women to the chuckling encouragement of Mr. Bush, an “Access Hollywood” host at the time, it just might have stifled the celebrity billionaire.

A body of psychological research shows that even mild pushback against offensive remarks can have an instant effect — as difficult as that can be, especially with a boss, a friend or a celebrity.

It is research worth considering in a political season when ethnic, racist and sexual slurs, not to mention general insults, seem to have become part of everyday chatter. Polls show that people are increasingly unhappy with the tenor of the national debate but unsure what to do about the decline in civility. Cont