Are Justices "Out of Step" on the Death Penalty?

Dahlia Lithwick has an article in today's Washington Post on "The Dying Death Penalty?" Lithiwck posits a "curious" development: Political leaders and the American public seems to have greater reservations about the death penalty, while the Supreme Court seems less likely than ever to impose constitutional constraints on how capital punishment is administered.

In a curious application of Newtonian physics, public and state support for capital punishment is steadily declining in America just as the resolve to maintain the death penalty seems to be hardening in the one arena where death-penalty policy once had seemed poised to change: the Supreme Court.
After summarizing the changes in public opinion and the grounds for questioning capital punishment, Lithick concludes:
But if for most Americans the time for stubborn certainty about the death penalty, at least as it's currently practiced, seems to be over, a court that is more certain than ever of its fundamental fairness looks grievously out of step with an American public willing to recognize the dangers of injustice, error and doubt.
The problem with Lithwick's formulation is its utter failure to distinguish between law and policy. For Lithwick, what makes some justices "out of step" with the American public is their unwillingness to curtail or invalidate capital punishment and belief that "if the death penalty in this country needs fixing, the state legislatures should do it, a process that's already beginning to happen." But this hardly follows. Indeed, the Court's death penalty jurisprudence should be determined by the justices' understanding of what the Constitution requires, not their feelings, misgivings, or personal sense of justice.

There are certainly grounds for misgivings about the death penalty as currently practiced, but that does not mean there is any legitimate basis for the Supreme Court to constrain or limit its use any more than it already has. And the Court is hardly "out of step" with the public if it leaves the American people ample ability to enact its policy preferences into law through the Democratic process. Indeed, what makes the Court "out of step" is when it engages in the opposite - prohibiting democratic majorities from resolving contentious political issues through their representatives and the democratic process.