Schaud v. Arizona. 501 U.S. 624, 632-33 (1991) (plurality opinion) (when a criminal statute provides alternative routes to a conviction, whether jurors must be unanimous with respect to a particular route depends on the answers to two questions: First, did the legislature intend to create different offenses or different means for violating a single offense? Second, if the legislature intended to create different means for violating the same offense, is that statutory definition constitutional under the Due Process Clause?).

Note: The Third Circuit elaborated on the Schaud framework in United States v. Edmonds, 80 F.3d 810 (3d Cir. 1996) (en banc). Thanks to Dan Kesselbrenner.
This helpful distinction is made also by the Fourth Circuit in the Royal decision, not an immigration case, but citing Descamps, 133 S. Ct. at 2285 (Rather than alternative elements, then, offensive physical contact and physical harm are merely alternative means of satisfying a single element of the Maryland offense. Consequently, because [t]he dispute here does not concern any list of alternative elements, the modified approach "has no role to play."). This rule should apply in immigration cases as well.