Donald Trump last week used some typically coarse language to describe Hillary Clinton, who responded by accusing Mr. Trump of sexism while announcing that she is unleashing Bill Clinton to campaign for her. This was too ripe an opening for Mr. Trump, who is now attacking Hillary for acquiescing in Bill’s predations against women.

Mr. Trump is rude and crude, but in this case he is raising an issue that rightly bears on the 2016 election campaign and the prospect of a third Clinton term. Mrs. Clinton wants to use her gender both as a political sword and shield to win the White House. The purpose is to make male politicians less willing to take her on, while reinforcing her main and not-so-subtle campaign theme that it’s time to elect the first woman President.

So she and her allies will try to spin any criticism as sexist. Even politically correct Bernie Sanders got this treatment after he said during a debate this autumn that “all the shouting in the world” wouldn’t keep guns out of the wrong hands. Mrs. Clinton later said that “I haven’t been shouting, but sometimes when a woman speaks out, some people think it’s shouting.” Against Republicans, she’ll play the “war on women” theme non-stop.

Yet no one in American politics better personifies a war on women than Mrs. Clinton’s husband. For readers too young to recall the 1990s, we aren’t merely referring to Trumpian gibes about female looks or “Mad Men” condescension. Mr. Clinton was a genuine sexual harasser in the classic definition of exploiting his power as a workplace superior, and the Clinton entourage worked hard to smear and discredit his many women accusers.

Start with “bimbo eruptions,” the phrase that Mr. Clinton’s Arkansas fixer Betsey Wright used to describe the women who had affairs with Bill. Gennifer Flowers almost derailed his primary campaign in 1992, until Hillary stood by her man on CBS ’s “60 Minutes” and the media portrayed Ms. Flowers as a golddigger.