Supreme Court Justice Stephen Breyer on Monday issued a dire warning about conservative justices’ increased willingness to buck established precedent, in an opinion widely interpreted as referencing the landmark abortion case Roe v. Wade. Dissenting in Franchise Tax Board of California v. Hyatt, a decision that overturned a 1979 decision on state sovereignty, Breyer wrote that “it is one thing to overrule a case when it ‘def[ies] practical workability,’” or when a ruling is no longer significant, citing the 1992 abortion case Planned Parenthood v. Casey. “It is far more dangerous to overrule a decision only because five Members of a later court come to agree with earlier dissenters on a difficult legal question.” Breyer added that he believes the court “surrendered to the temptation” to overrule a decision that they didn’t like, despite the fact that it “caused no serious practical problems in the four years since we decided it.” He concluded that “Today’s decision can only cause one to wonder which cases the court will overrule next.” The comment has widely been seen as alluding to Roe v. Wade, the landmark 1973 ruling that enshrined a woman’s right to an abortion. Now that five conservative justices sit on the bench, many leaders of conservative states have pledged to bring down Roe.