Stanford Law Professor Richard Thompson Ford wrote for Slate’s “Jurisprudence” column about the Supreme Court of the United States’ decision in Ledbetter v. Goodyear Tire and Rubber Co. Here’s an excerpt:

…Justice Samuel Alito wrote for the majority of the court that an employer who shortchanged a female employee for years, up until she retired, discriminated on the basis of sex only the first time this happened. Because she didn’t sue right away—she probably didn’t know she was being shortchanged until later—the court barred her claim as untimely, even though her employer continued to pay her less than men doing the same work until she left.

It’s a bad decision. And at first, the Ledbetter opinion reads like ideological warfare: the right wing of the court struggling against precedent to gut a civil-law statute. But that may be unfair. In fact, the court’s argument follows from a widespread—though misguided—obsession with state of mind that many conservatives and liberals share.