The U.S. Supreme Court on Monday overturned a 40-year-old legal precedent regarding state sovereignty, leading Justice Stephen Breyer to question in a dissenting opinion which longstanding rulings the court may choose to toss out next.

What happened

Monday’s decision pertained to Franchise Tax Board of California v. Hyatt, a tax dispute involving inventor Gilbert P. Hyatt who was accused of lying about when he moved from California to Nevada in order to escape the former state’s income taxes.

In 1998, Hyatt sued the California board in a Nevada state court over what he argued were extreme measures it had taken to prove its claim, including sending an auditor to sort through his trash, enlisting estranged family members against him and releasing his address and Social Security number to newspapers.

A jury awarded Hyatt $490 million in damages, reduced to $1 million by the Nevada Supreme Court. The board then appealed to the U.S. Supreme Court to overturn Nevada v. Hall, a 1979 decision that allows individuals to sue a state in the courts of a different state. The high court split 4-4 over the matter, leaving Nevada v. Hall intact for the time being.

But in a 5-4 decision on Monday, the Supreme Court overturned the 40-year-old decision, arguing that “states retain their sovereign immunity from private suits brought in courts of other states.”

How Breyer responded

The decision split the justices along conservative and liberal lines, with Justice Clarence Thomas leading the charge and deeming Nevada v. Hall “an incorrect resolution of an important constitutional question.”

In a dissenting opinion joined by Justices Ruth Bader Ginsburg, Sonia Sotomayor and Elena Kagan, Breyer argued that the majority shouldn’t be so quick to overturn longstanding decisions that have provided “legal stability” in the U.S. for decades.

“Each time the Court overrules a case, the Court produces increased uncertainty,” Breyer wrote. “To overrule a sound decision like Hall is to encourage litigants to seek to overrule other cases; it is to make it more difficult for lawyers to refrain from challenging settled law; and it is to cause the public to become increasingly uncertain about which cases the Court will overrule and which cases are here to stay.”

Breyer added that although justices may disagree with previous rulings, they should only seek to overrule decisions shown to be “obviously wrong.”

“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 wrote.

Thomas, joined by Chief Justice John Roberts Jr. and Justices Samuel Alito Jr., Neil Gorsuch and Brett Kavanaugh, “surrendered to the temptation to overrule Hall even though it is a well-reasoned decision that has caused no serious practical problems in the four decades since we decided it,” Breyer said.

“Today’s decision can only cause one to wonder which cases the Court will overrule next,” he wrote.

Where Roe v. Wade stands

Breyer didn’t mention Roe v. Wade in his dissent, but the implications were clear. The justice cited portions of Planned Parenthood v. Casey, a case that reaffirmed Roe v. Wade while also upholding certain provisions of Pennsylvania’s abortion law. The portions Breyer cited in his dissent on Monday specifically discuss why Roe should be upheld.

And he has good cause to sound the alarm. State legislatures in portions of the Deep South and Midwest are slowly enacting more and more restrictive measures that could essentially spell the end of the constitutional right to abortion, granted by Roe, in those states.

Alabama is close to approving a bill that the state’s lieutenant governor admitted is a direct attempt to get Roe v. Wade overturned. The bill, called the Human Life Protection Act, would make it a felony for a doctor to perform an abortion.

Republican Gov. Brian Kemp of Georgia this month signed a controversial “heartbeat bill” that bans abortion as soon as a doctor can detect a fetal heartbeat, which usually happens at around six weeks into a pregnancy and before most women are aware that they’re pregnant.