In my online searches, I encountered some feminists who seemed genuinely to subscribe to the phrase. But overwhelmingly, the Twitterati deploying the phrase were conservatives, wielding it as a whip. Why?

Because the right knows what #MeToo activists do well to keep in mind: Peril lies in purity. If the pluralism of the women’s movement can be reduced to rigid boilerplate in the public mind, then the future of #MeToo will have more to lose from a single untruthful woman whom it’s sworn to defend than from boatloads of predatory men.

This is why “Believe All Women” is not an amplification of “Believe Women,” but its negation. As Mr. Morales Henry at the Schlesinger Library told me, after several days of analyzing the use of the two hashtags, “It looks like #BelieveAllWomen, especially recently, is being used in opposition to #BelieveWomen.” Its use spikes on occasions when allegations are made against a liberal politician — often with companion hashtags decrying a double standard.