By the late 1980s, President Ronald Reagan had made three appointments to the Supreme Court. In 1989, the Court upheld restrictions on abortion passed by the Missouri legislature. Then President George H. W. Bush made two additional appointments. When the Court took up another abortion case during the term ending in 1992, many people expected that it would overturn Roe v. Wade.

It didn’t. Instead, three of the justices appointed by Reagan and Bush — Anthony Kennedy, Sandra Day O’Connor, and David Souter — wrote an opinion in Planned Parenthood v. Casey that reaffirmed Roe while also modifying it.

Pro-lifers were on …