In October, the U.S. Supreme Court heard oral arguments in an important case that asks whether Congress violated Article I, Section 1 of the Constitution by delegating its lawmaking authority to the executive branch.

That question is at the heart of Gundy v. United States, in which convicted sex offender Herman Avery Gundy is challenging the Sex Offender Registration and Notification Act of 2006 (SORNA), which among other things requires convicted sex offenders to register, check in periodically in person, and share personal information with the authorities.

The law also contains this provision: "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." In other words, Congress left it up to the A.G. to determine how to deal with the estimated 500,000 individuals whose sex crime convictions predate SORNA's passage.

"SORNA's delegation provision grants unguided power to the nation's top prosecutor to expand the scope of criminal laws and to impose burdensome, sometimes lifetime registration requirements on hundreds of thousands of individuals," Sarah Baumgartel, Gundy's attorney, told the Supreme Court in October. That delegation of power, Baumgartel maintained, "combines criminal law-making and executive power in precisely the way that the Constitution was designed to prohibit."

If we read between the lines of the oral arguments, a couple of members of the Supreme Court seemed to be leaning toward siding with Gundy.

"The specific statutory section dealing with pre-enactment offenders says unambiguously that the attorney general decides whether, how, when, and who. So you don't even know if you're going to be subject to this law," observed Justice Neil Gorsuch. "We say that vague criminal laws must be stricken.…What's vaguer than a blank check to the attorney general of the United States to determine who he's going to prosecute?"

Justice Sonia Sotomayor continued that line of questioning. "I think a fundamental issue that Justice Gorsuch has been aiming at is—especially in criminal law—is it just to delegate to the attorney general a fundamental question about who gets covered or doesn't get covered by a statute?" she asked. "That seems like at the core of what a law is: If someone does X act, you're covered or you're not."

We won't know until the current term ends in June 2019 whether a majority of the Supreme Court will see this case in the same light as Gorsuch and Sotomayor. If they do, it will be a significant win both for criminal justice reformers and for critics of executive overreach.