Does the Sixth or Eighth Amendment matter more for jury's role in capital punishment?

The question in the title of this post is the primary uncertainty likely to impact Supreme Court debate over Florida's capital punishment system during tomorrow's scheduled oral argument in Hurst v. Florida.  Helpfully, Lyle Denniston has this lengthy preview post at SCOTUSblog titled "Defining the jury's role on death penalty," and here are excerpts:

For years, the Supreme Court has been engaged in an energetic effort to enhance the role of the jury in criminal courts. No part of that has been more actively pursued than deepening the jury’s involvement in sentencing — a part of the process long dominated by trial judges. A new case from Florida, set for argument at 11 a.m. on Tuesday, provides a new test.

Florida is the last state to hold out against a common requirement that jurors must be unanimous in both specifying why a convicted individual is eligible for a death sentence and recommending a sentence. Juries in Florida death penalty cases have only an advisory role to begin with, and even that influence on the judge is potentially lessened by the lack of unanimity and by the judge’s authority to make the key decisions anyway.

The Court is examining the case of a brutal slaying at a Popeye’s fast-food restaurant in Pensacola, Fla. (Hurst v. Florida), to determine how far a state may go to assign the important decisions on death sentencing to the judge. The Justices attempted to curb that role, and give more of it to the jury, in a 2002 decision but the Florida Supreme Court has essentially exempted the state’s capital punishment process from that ruling.

In Ring v. Arizona thirteen years ago, the Supreme Court ruled that a judge may not make the factual findings about “aggravating factors” — the seriousness of the crime that can make an individual eligible to be sentenced to death — because that role under the Sixth Amendment belongs to the jury. The Court has said repeatedly that, if a potential sentence is to be made more severe, the enhancement must be based upon the jury’s findings.

The Court, however, has never ruled that juries must be used in the sentencing phases of a case in which a death sentence is a possibility, and it has never ruled that a jury recommendation of a death sentence must be by a unanimous vote. It has allowed guilty verdicts by less than unanimous votes in cases involving lesser crimes. The case set for a hearing next Tuesday could provide new interpretations on both of those issues....

Florida law splits up the roles on death sentencing between the jury and the judge. The jury’s advisory role is to ultimately recommend a sentence to the judge. To do that, the jury weighs aggravating and mitigating factors and decides whether to recommend a death sentence. It can make that final recommendation on a split vote — it must be at least seven to five, as it was in Hurst’s case. But there is no need for even a majority of jurors to agree on even one of the aggravating factors the jurors as a group had apparently indicated did exist.

The sentencing duty then shifts to the judge, who does the same weighing process of the two kinds of factors; in doing so, the judge is not bound by what the jury concluded. The judge then decides for or against a death sentence, again with no duty to follow the jury’s recommendation.

The Florida Supreme Court, upholding that process as used in Hurst’s case, found no constitutional problem with the role of either the jury or the judge. The state court divided four to three, with the dissenting justices arguing that the Florida approach violates both the Sixth and Eighth Amendments and deviates from the Supreme Court’s ruling in Ring v. Arizona.

Hurst’s lawyers took the case on to the Supreme Court, raising two multi-faceted questions, with most of them focusing on the split role of judge and jury. The Court granted review in March, rephrasing the issue to be whether the Florida scheme violates either the Sixth Amendment or the Eighth Amendment “in light of this Court’s decision in Ring v. Arizona.” The order did not specify whether it would consider Hurst’s argument that he also had a claim of mishandling in his trial of a mental disability claim, but the Court did not appear to have accepted that for review and it has dropped out of the case.

Hurst’s brief on the merits largely separates the arguments between the Sixth Amendment, claiming that provision is violated by the jury’s limited role in finding whether Hurst was eligible for a death sentence, and the Eighth Amendment, claiming that provision is violated by allowing the judge to impose the sentence after a split verdict by the jury. However, he also levels a separate Sixth Amendment challenge to the judge’s role in imposing a death penalty....

Florida’s brief on the merits noted that the Supreme Court has examined its capital punishment scheme at least four times before and has not found it to be flawed under the Constitution. The state also insisted that Hurst’s lawyers had exaggerated what is required under Ring v. Arizona. That decision, it contended, only mandates a role for the jury in the death-eligibility analysis, and does not insist that it have a role in the actual selection of the sentence to be imposed.

As fans of Ring v. Arizona should recall, a few of the Justices still on the Court now considered these issues to be primarily of Sixth Amendment concern (Justices Scalia, Thomas and Ginsburg), whereas some other of the Justices still on the Court viewed these issues primarily from an Eighth Amendment perspective (Justices Kennedy and Breyer). And, notably, the four newer Justices have had a lot of distinct (and differing) things to say about both the Sixth and Eighth Amendments in recent years. How all this will add up to a majority ruling in Hurst remains to be seen, but I will suggest that anyone sentenced to death in Florida after a non-unanimous jury recommendation already ought to be getting ready to file a new habeas petition as soon as we get a ruling in Hurst.