Whenever the United States Supreme Court issues an opinion stating or creating expanded rights to criminal defendants, those already convicted who might benefit from the opinion, wonder whether the rule will have retroactive or retrospective effect, or only prospective effect.

Today the U.S. Supreme Court, 6-3, strengthened the circumstances for when such retroactive effect is given. Montgomery v. Louisiana , __ U.S. __ (Jan. 25, 2016). Montgomery gives retrospective effect to Miller v. Alabama, 567 U. S. ___ (2012), which prohibits mandatory, versus discretionary, life without parole sentences for those who committed crimes while under eighteen years old, with Montgomery limiting the available retrospective Miller relief to parole agency consideration, rather than a new sentencing trial.

Montgomery confirms that:

Teague [v. Lane, 489 U. S. 288 (1989)] recognized, however, two categories of rules that are not subject to its general retroactivity bar. First, courts must give retroactive effect to new substantive rules of constitutional law. Substantive rules include “rules forbidding criminal punishment of certain primary conduct,” as well as “rules prohibiting a certain category of punishment for a class of defendants because of their status or offense.” Penry v. Lynaugh, 492 U. S. 302, 330 (1989); see also Teague, supra, at 307. Although Teague describes new substantive rules as an exception to the bar on retroactive application of procedural rules, this Court has recognized that substantive rules “are more accurately characterized as . . . not subject to the bar.” Schriro v. Summerlin, 542 U. S. 348, 352, n. 4 (2004). Second, courts must give retroactive effect to new “‘“watershed rules of criminal procedure” implicating the fundamental fairness and accuracy of the criminal proceeding.’” Id., at 352; see also Teague, 489 U. S., at 312–313.

Montgomery.

Dissenting Justice Scalia, joined by Justices Thomas and Alito, claims that Montgomery creates a retroactivity rule from whole cloth. With his dissent, Scalia may have been seeking to lobby majority opinion author Justice Kennedy — a frequent swing voter between the four most conservative justices and the remaining justices — and majority-joining Chief Justice Roberts, as well as to lobby any new appointees to the court.

In the meantime, Montgomery is of course the law of the land.