The Supreme Court (Jacquelyn Martin/AP)

Supreme Court justices seemed troubled Tuesday by Florida’s unique system of imposing a death sentence, as they considered a challenge that argues the process gives judges too much power and juries too little in assigning the ultimate punishment.

The case was one of two important criminal justice issues that the court considered in a longer-than-usual session. The court also heard arguments about whether juveniles sentenced to life in prison without parole should be able to challenge those sentences, since the court has ruled that states cannot make such punishment mandatory.

But on the issue about juveniles, the justices got stuck over whether the case they had accepted from Louisiana actually gave them jurisdiction to settle the issue for the rest of the country. One option might be to accept a different case.

In the Florida death-penalty case, challengers said the state law conflicts with the Supreme Court’s decision in 2002, which said that a defendant has the right to have a jury — rather than a judge — decide whether something extraordinary about the crime makes the defendant eligible for the death penalty.

“Under Florida law, Timothy Hurst will go to his death despite the fact that a judge — not a jury — made the factual finding that rendered him eligible for death,” said Washington lawyer Seth P. Waxman.

Hurst was convicted of the 1998 murder of Cynthia Lee Harrison, his coworker at a Popeyes fast-food restaurant in Pensacola.

“Florida, and Florida alone,” Waxman said, has such a “muddle” of responsibilities between a judge and jury. Florida is second only to California in the number of death-row inmates — and Waxman said there are numerous reasons to think Florida’s approach is unconstitutional.

As in other places, Florida requires a jury to consider aggravating circumstances that would make a defendant eligible for the death penalty — for instance, that the crime was committed during a robbery, or was particularly “heinous, atrocious or cruel” — along with mitigating circumstances, such as a defendant’s low IQ or childhood abuse.

But Florida does not require the jury to be unanimous in recommending death. In Hurst’s case, the jury found two aggravating circumstances on a vote of 7 to 5. But it is unclear whether all seven agreed on both, or, for instance, whether four agreed on one and three on the other.

The Florida jury was also told that its recommendation was not binding and that it was up to the judge to make a final decision. And even then, the judge could consider evidence that the jury did not.

Any one of those factors would make the state’s law suspect, Waxman said, but together they surely make it unconstitutional.

Waxman seemed to have support from the justices who generally are skeptical about the death penalty. “The whole appeal process suggests that the crucial death-eligibility determination is being made by the judge,” said Justice Elena Kagan, adding that would seem to violate the court’s 2002 decision.

Florida Solicitor General Allen Winsor acknowledged, under questioning, that in some cases, a judge can even overrule a jury’s recommendation that a defendant receive life in prison and impose a death sentence. But, he said, that has not happened since 1999.

Winsor said that the division of responsibility between the judge and jury has benefits, providing safeguards. And he said that it doesn’t matter whether the judge makes the final decision as long as the jury recognizes aggravating circumstances that make the defendant eligible for the death penalty.

But Justice Antonin Scalia, a strong proponent of capital punishment, signaled concerns. Waxman had said that because the jury’s recommendation is essentially advisory, jurors may not approach their role with due gravity.

“I’m talking about what responsibility the jury feels,” Scalia told Winsor.

The case is Hurst v. Florida.

Life sentences for juveniles

In the juvenile case, the court was exploring the next step after it decided three years ago that mandatory life sentences without parole were off the table.

The court ruled 5 to 4 at the time that judges must be allowed to at least consider mitigating circumstances, such as a lack of maturity, an underdeveloped sense of responsibility or whether minors are more open to rehabilitation, before rejecting the prospect of parole.

Usually, the court’s decisions are not retroactive. But the issue is whether the court’s 2012 decision in Miller v. Alabama was such an important change in the law that those who were sentenced before the decision should be allowed to ask courts to reconsider their punishments.

Kagan, who wrote the decision in Miller, argued that it was retroactive. The decision changed the range of options available to states sentencing juvenile defendants convicted of murder, Kagan said.

But S. Kyle Duncan, a Washington lawyer arguing for Louisiana, said the change was a procedural one, because a judge can still impose life without parole, after considering the factors the Supreme Court outlined.

Someone who received such a sentence before the Miller decision “is not facing a punishment that the law cannot impose on him” now, Duncan said.

The case was brought by Henry Montgomery, who as a 17-year-old in 1963 shot and killed Sheriff’s Deputy Charles Hurt. Montgomery is now 69 and says his rehabilitation in prison should make him eligible to be considered for parole. The Louisiana Supreme Court rejected his claim.

The U.S. Supreme Court justices were concerned about whether the Louisiana court’s decision was based on state law rather than federal law. The U.S. Supreme Court does not generally review decisions based on only state law.

Lawyers for Montgomery, Louisiana and the U.S. government all told the justices that the U.S. Supreme Court has jurisdiction. “As a practical matter, this court ought to weigh in,” Duncan said.

“We weigh in when we have jurisdiction,” Scalia responded.

If the court were to decide it does not have jurisdiction, the option would be to take a case that has arisen through federal courts.

The case is Montgomery v. Louisiana.