Abstract: The Supreme Court’s constitutional regulation of the American death penalty has yielded a plethora of doctrines that have shaped an alternative criminal justice process that is (mostly) limited to capital cases. Many of these doctrines offer a vision and practice of “roads not taken” in the ordinary criminal justice process that would be attractive improvements in that larger system. We consider three of these doctrines: (1) more searching review of the proportionality of sentencing outcomes; (2) imposition of a requirement of individualized sentencing that has led to the investigation and presentation of in-depth evidence in mitigation; and (3) greater regulation of the adequacy of defense counsel that has moved closer to a “checklist” model of mandated practices. Each of these doctrines was born and developed under the Court’s “death is different” regime of constitutional regulation, and each of them has to some limited extent moved beyond the strictly capital context into the broader criminal justice process. We explain how these alternative models present attractive improvements for the broader noncapital system—a view that casts the Court’s regulation of the American death penalty as a progressive laboratory that can yield alternative, more protective, and more idealized processes for the ordinary criminal justice system. Yet we also caution that the “differentness” of death—and of juvenile offenders, the noncapital context to which the Court is most likely to import its death penalty innovations—can also serve to normalize and entrench the less protective, less idealized practices that exist outside of these realms.