What happens to rule of law if the law keeps changing?

Interpretations of law change over time, of course. But a case before the U.S. Supreme Court highlights what can happen when politics flip-flop so wildly and quickly.

When Justice Stephen Breyer began to speak, Amy Hagstrom Miller could barely believe it.

As he continued, she began to wonder if she was in the U.S. Supreme Court at all, or if she was dreaming.

The headline from Justice Breyer’s majority opinion four years ago, in Whole Woman’s Health v. Hellerstedt, was that the 5-to-4 decision found a Texas law unconstitutional in...