In 1985 a prominent liberal legal figure argued that Roe v. Wade, the Supreme Court decision that established a constitutional right to an abortion, was a “heavy-handed judicial intervention” that “was difficult to justify and appears to have provoked, not resolved, conflict.” The writer was Ruth Bader Ginsburg, now an associate justice on the U.S. Supreme Court—and also now a strong supporter of Roe. Ginsburg isn’t the only backer of abortion rights to have taken issue with the 1973 decision. In 1995, for example, the University of Chicago’s Cass Sunstein, a superstar among liberal law professors, wrote in the Harvard...