In a surprise decision from the U.S. Supreme Court on Monday, Chief Justice John Roberts provided the pivotal fifth vote to strike down a Louisiana law targeting abortion clinic providers, arguing that the Justices should not overturn a decision made on a similar law back in 2016.

"The legal doctrine of stare decisis requires us, absent special circumstances, to treat like cases alike," Roberts wrote, referring to the Texas case from four years ago.

"The Louisiana law imposes a burden on access to abortion just as severe as that imposed by the Texas law, for the same reasons," Roberts wrote.

But in 2016, the Chief Justice voted to uphold that Texas law, as this time Roberts quoted Black's Law Dictionary from 1696 on stare decisis.

"It has long been “an established rule to abide by former precedents, where the same points come again in litigation; as well to keep the scale of justice even and steady, and not liable to waver with every new judge’s opinion," Roberts quoted.

Still, Roberts seemed to leave the door open to other abortion challenges.

Like a Texas case from 2016, the Louisiana law required abortion providers to have admission privileges at hospitals near their clinics.

It was another example of Roberts seemingly now taking on the role which had long been occupied by former Justice Anthony Kennedy - the centrist vote between two battling factions of four conservative and four liberal justices.

In recent weeks, Roberts has provided the fifth vote to stop the Trump Administration from ending the DACA program, to extend anti-discrimination protections to LGBTQ workers, and to allow states to limit church services because the Coronavirus outbreak.

"We are winning these cases by the skin of our teeth and because Roberts fears for the Court's legitimacy with the public," said Brian Fallon, who leads a progressive group demanding change on the Supreme Court.

The latest decision from Roberts prompted immediate grumbling among conservative Republicans.

"What’s next, Chief Justice Roberts? Our Second Amendment rights?" tweeted Rep. Jim Jordan (R-OH).

But while Democrats celebrated the unlikely victory today, they also reminded their voters of the importance of the upcoming election.

"Another reason 2020 will be the most important election of our lifetimes," said Rep. Joe Cunningham (D-SC).