Ronald S. Kammerer, Jr. v. The State of Wyoming, 2014 WY 50

Kammerer pleaded guilty in New Jersey (1993) to second-degree sexual assault, later moved to Gillette, Wyoming, and was required to register under Wyoming’s Sex Offender Registration Act (WSORA).
In 2012 Kammerer was charged with failing to register; he moved to dismiss on ex post facto grounds before trial; motion denied; jury convicted him and found prior failure-to-register for sentence enhancement.
District court sentenced Kammerer to 4–7 years; he appealed challenging WSORA under the federal and Wyoming ex post facto prohibitions.
WSORA requires lifelong registration for listed convictions (with limited petition relief), periodic in-person verification, reporting of travel (21 days before leaving the U.S.), disclosure of identifying and offense information, public internet access, and neighborhood notification.
The Court applied de novo review, presuming statutes constitutional and resolving doubts for validity; relied on the Smith v. Doe analytic framework (legislative intent then Mendoza‑Martinez factors) and Wyoming precedent (Snyder, In re JJF).

Issue	Plaintiff's Argument (Kammerer)	Defendant's Argument (State)	Held
Does WSORA violate the U.S. Constitution’s ex post facto clause?	WSORA’s amendments make registration, active notification, frequent in‑person reporting, movement and residency controls punitive and retroactive punishment.	WSORA is regulatory, aimed at public safety and law enforcement; any punitive effects are insufficient to overcome legislative intent.	Held: No violation — act is civil/regulatory; Mendoza‑Martinez factors do not show clear punitive purpose or effect.
Does the Wyoming Constitution provide greater ex post facto protection so WSORA is invalid under state law?	Wyoming’s provision affords broader protection than the federal clause, making WSORA unconstitutional under state law.	No controlling Wyoming authority establishing broader protection; federal framework adopted in state decisions; review for plain error would not change result.	Held: No — Wyoming Constitution not shown to provide greater protection; claim fails.
Did the district court commit plain error by not finding greater state protection? (State raised)	—	The State urged plain‑error review and argued no unequivocal rule supports broader state protection.	Held: No plain error; no persuasive authority that Wyoming’s clause is broader; affirm conviction.

Smith v. Doe, 538 U.S. 84 (U.S. 2003) (two‑step test: legislative intent then whether effects are so punitive as to negate civil purpose; applies Mendoza‑Martinez factors)
Snyder v. State, 912 P.2d 1127 (Wyo. 1996) (Wyoming precedent holding WSORA regulatory, not punitive)
Kennedy v. Mendoza‑Martinez, 372 U.S. 144 (U.S. 1963) (multi‑factor test to distinguish civil regulatory measures from punishment)
Kansas v. Hendricks, 521 U.S. 346 (U.S. 1997) (civil confinement of dangerous sex offenders and deference to legislative intent regarding regulatory objectives)
In re JJF v. State, 132 P.3d 170 (Wyo. 2006) (reaffirming Wyoming’s sex offender statutes as regulatory)
Femedeer v. Haun, 227 F.3d 1244 (10th Cir. 2000) (notification/registration not punitive; instructive on Mendoza‑Martinez application)
E.B. v. Verniero, 119 F.3d 1077 (3d Cir. 1997) (distinguishing public dissemination of official criminal information from historical shaming punishments)
ACLU v. Masto, 670 F.3d 1046 (9th Cir. 2012) (active public notification does not by itself render statute punitive)