Gundy v. United States, 588 U.S. 128

Congress enacted the Sex Offender Registration and Notification Act (SORNA) in 2006 to create a "comprehensive national system" for sex-offender registration and to strengthen criminal penalties for failure to register.
SORNA’s §20913(b) sets the general initial-registration rule: offenders must register before completing a sentence of imprisonment (or within three business days if not imprisoned).
§20913(d) addresses pre-Act offenders (convicted before SORNA) and provides: "The Attorney General shall have the authority to specify the applicability of the requirements of this subchapter to sex offenders convicted before the enactment of this chapter, and to prescribe rules for the registration of any such sex offenders…who are unable to comply with subsection (b)."
The Attorney General issued regulations applying SORNA to pre-Act offenders; Herman Gundy (a pre-Act offender) was later convicted under 18 U.S.C. §2250 for failing to register and challenged §20913(d) as an unconstitutional delegation of legislative power.
Lower courts (and eleven circuits) rejected Gundy’s nondelegation challenge; the Supreme Court granted certiorari to decide whether §20913(d) violates the nondelegation doctrine.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether §20913(d) impermissibly delegates legislative power to the Attorney General	Gundy: §20913(d) grants the AG plenary, unconstrained power to decide whether and how SORNA applies to pre-Act offenders (including permanent exemptions) — unconstitutional delegation	Government/Majority: read in context and purpose, §20913(d) only permits limited, transitional discretion to address "feasibility" and implementation; Congress required coverage of pre-Act offenders and set the policy	Court affirmed: §20913(d) constitutional when interpreted to require the AG to apply SORNA to pre-Act offenders "as soon as feasible," a sufficiently intelligible principle
Proper interpretation of §20913(d) (scope of "specify the applicability")	Gundy: phrase standing alone allows AG to choose whether to apply SORNA at all	Gov./Majority: interpret statute holistically (text, purpose, definition of "sex offender," legislative history) to limit AG authority to time-limited, feasibility-based implementation decisions	Court: §20913(d) means "specify how and when" to apply SORNA during transition; does not permit permanent nonapplication

Wayman v. Southard, 10 Wheat. 1 (1825) (early articulation that Congress may not transfer strictly legislative powers)
J. W. Hampton, Jr., & Co. v. United States, 276 U.S. 394 (1928) ("intelligible principle" formulation for delegations)
A. L. A. Schechter Poultry Corp. v. United States, 295 U.S. 495 (1935) (invalidating delegation lacking standards)
Panama Refining Co. v. Ryan, 293 U.S. 388 (1935) (invalidating abdication of legislative standards)
Mistretta v. United States, 488 U.S. 361 (1989) (upholding broad delegations where an intelligible principle exists)
Whitman v. American Trucking Assns., Inc., 531 U.S. 457 (2001) (reinforcing permissive, non-demanding intelligible-principle standard)
Reynolds v. United States, 565 U.S. 432 (2012) (prior interpretation that SORNA does not apply to pre-Act offenders of its own force and that AG must specify applicability; limited AG authority to address feasibility)
Yakus v. United States, 321 U.S. 414 (1944) (statute upheld where Congress provided standards and procedure for executive implementation)