Let me first say that it is very likely the government will ask for a rehearing
en banc because, if it does not, the panel's opinion on
Chevron deference in (some) criminal cases will become binding circuit precedent. The Sixth Circuit does not hear a lot of cases
en banc, but this could be one they take. I doubt the government would seek Supreme Court review unless going this route first. Even then, it might not seek Supreme Court review since this is a preliminary injunction which is restricted by its own terms to the states in the Sixth Circuit (Kentucky, Michigan, Ohio, and Tennessee) and to "the parties themselves." Slip opinion at 36. The Supreme Court might have another shot at it following final determination of the issues. The Sixth Circuit also noted that the Supreme Court has often allowed circuit splits for a time so that more courts could weigh in on the issues.
The decision not to give
Chevron deference to agency interpretation of criminal statutes is much more impactful than the bump-stock issue itself. Without getting too lawyerly, the
Chevron case provides that courts give administrative agencies a great deal of deference when interpreting a statute. But,
Chevron did not involve criminal penalties.
The Sixth Circuit opinion rejected the primary rationale for
Chevron deference when interpreting statutes with criminal penalties (or at least some of them).
Chevron is premised on the assumption that administrative agencies have expertise of the subject matter they regulate and that this expertise should be given weight. The majority opinion rang a church bell, warning of of Executive Branch overreach: "
Federal criminal laws are not administrative edicts handed down upon the masses as if the administrators were God delivering the Ten Commandments to Moses on Mount Sinai." Slip op. at 20 (emphasis added).
The court then summarized its reason for rejecting this rationale for
Chevron deference:
In sum, for criminal statutes, where the primary question is what conduct should be condemned and punished, the first rationale of Chevron deference—deferring to an agency’s expertise—is unconvincing because the agency’s technical specialized knowledge does not assist in making the value-laden judgment underlying our criminal laws.
Slip op. at 21.
The majority also thought the agency interpretation violated separation of powers:
Because the community has the right to determine what moral wrongs should be punished—a practice that predates our Constitution—that responsibility may be entrusted to only the branch most accountable to the people: the legislature. And it may not be blithely delegated away.
Slip op. at 26.
The court also thought that an agency's interpretation of an ambiguous statute against a person charged violated the rule of lenity in criminal cases and raised concerns about fair notice in this particular instances because of a change in the agency's interpretation.
Finally, the majority opinion then rejected the government's interpretation that a bump stock was a machine gun since the shooter only pulled his or her finger only once. Instead, it interpreted the statute to mean that there was no machine gun where the mechanical trigger itself would be depressed (and released) for each shot, as is the case where a bump stock is employed.
I've only hit a couple of high points in the opinion. There's lots of discussion about case law and why the court felt free to not follow the lead of two other circuits on this issue.