More mandatory sentencing minimums for gun offenders could be triggered after the U.S. Supreme Court’s Dec. 10 ruling in a case involving the oft-litigated Armed Career Criminal Act.

The unanimous opinion by Justice Stephen G. Breyer is the first decision in an argued case this term in which Justice Brett M. Kavanaugh participated. It was argued Oct. 9 during Kavanaugh’s first oral argument appearance after his contentious confirmation battle.

Facing sentencing on federal gun charges, Victor Stitt and Jason Sims challenged the use of their state burglary convictions to enhance their federal prison terms under the career criminal act. It imposes 15-year mandatory minimums for gun offenders with three prior “violent” convictions.

The act has prompted much litigation over the years, including in another case argued the same day that’s still awaiting a decision from the justices. One source of the voluminous litigation has been confusion over how to apply various states’ criminal statutes to the federal sentencing law.

“The decision is obviously a disappointment and one senses the Court’s frustration with the piecemeal decisions that must be made regarding this statute,” Sidley Austin’s Jeffrey T. Green told Bloomberg Law. He and other attorneys filed an amicus brief with the court on behalf of the National Association of Criminal Defense Lawyers.

The specific issue here was whether a prior state conviction for burglary of a “nonpermanent or mobile structure that is adapted or used for overnight accommodation” can qualify as a “violent” enhancement under the federal act.

It can, Breyer wrote for the court.

Congress viewed burglary as inherently dangerous because it “creates the possibility of a violent confrontation between the offender and an occupant, caretaker, or some other person who comes to investigate,” he wrote, citing the court’s 1990 decision in Taylor v. United States.

That same logic applies here, if not to a greater degree, Breyer reasoned for the court. “A burglary is no less a burglary because it took place at a summer home during the winter, or a commercial building during a holiday.”

But the court’s decision “will only engender more questions about the subjective use of a vehicle or boat—whether, for example, a fold down cot on a food truck makes it the equivalent of a ‘dwelling,’” said Green. “More than anything else,” he said, “these matters of narrow line drawing seem to fall within the ‘rule of lenity,’ whereby unless the legal line is very obvious, the additional criminal punishment cannot be imposed.”

Another lawyer—who agrees with the decision—nonetheless thinks it highlights troubling issues with the way the court deals with these sentencing cases.

“I think it’s a correct decision as far as it goes,” Kent Scheidegger of the Criminal Justice Legal Foundation told Bloomberg Law.

But the “real problem,” he said, is the “categorical” approach adopted in Taylor.

“Under that approach, prior convictions for burglary which are, in fact, burglary as traditionally defined may either count as ‘strikes’ or not, depending on the irrelevant circumstance of whether the state law does or does not expand a tad beyond what the Supreme Court considers to be ‘generic burglary,’” said Scheidegger, who has filed scores of briefs in the Supreme Court siding with the government in criminal cases.

He said the Taylor rule is “just wrong” because “convicted criminals should be punished according to what they did and what they have done before, period.”

Under the Taylor rule, he said, “two criminals who broke into houses and stole things (classic burglary) may be punished very differently by federal courts for later weapons violations just because their priors were in different states.”

The high court reversed the U.S. Court of Appeals for the Sixth Circuit’s ruling for Stitt. It vacated the U.S. Court of Appeals for the Eighth Circuit’s ruling for Sims and sent it back for more analysis on the state statute in his case.

A lawyer for the defendants declined comment. The Justice Department didn’t immediately respond to a request for comment.

The case is United States v. Stitt, U.S., 17-765, reversed 12/10/18, United States v. Sims, U.S., 17-766, vacated and remanded 12/10/18.