Respect for precedent has been a cornerstone of the American legal system. But what happens if, to “fix mistakes” in the law, courts favor rapid change that the public could not have anticipated?

When the Florida Supreme Court ruled late last month that a unanimous jury is not required for the state to hand down a death sentence, the decision reverberated in the state prisons that house hundreds of felons already sentenced to death.

The legal wrangling over their fate overnight became “chaos,” says Marty McClain, a death-penalty lawyer.

After all, only four years earlier, Florida had struck down the power of judges, not juries, to decide whether or not to execute convicted felons. That ruling followed a landmark U.S. Supreme Court finding that Florida’s system for capital sentencing was unconstitutional and led nearly 100 inmates on death row there to challenge their sentences.

But a new conservative majority on Florida’s highest court has begun taking a shredder to this and other seemingly settled rulings, part of a national rollback of what conservatives see as an era of liberal judicial activism. That ideological rollback is embodied in President Donald Trump’s appointment of 187 U.S. judges, including two to the Supreme Court, since 2017. Under his watch, three U.S. appeals courts have flipped from liberal to more conservative majorities.

In its Jan. 23 verdict, the Florida Supreme Court said it had “got it wrong” in 2016 when it curbed the power of judges to effectively overrule split juries on capital cases. That case, Hurst v. State, was supposed to have a “limited practical effect on the administration of the death penalty,” Chief Justice Charles Canady wrote. But he said it had led to legal maneuvering that was undermining “decades of settled Supreme Court and Florida precedent.”

Critics say the court’s abrupt reversal – the 2016 ruling was more than a decade in the making – has caused chaos for inmates on death row and attorneys like Mr. McClain. Some argue it violates the legal concept of stare decisis, which holds that rulings that overturn established law should be “well thought-out and pretty rare,” says Kenneth Williams, a professor at the South Texas College of Law Houston.