A state drug conviction can trigger a mandatory 15-year sentence under the Armed Career Criminal Act if it involved a drug on the federal schedules at the time of that conviction, the U.S. Supreme Court ruled Thursday.

In a 6-3 decision, the justices sided with the federal government. The decision clarifies, in light of changing federal drug laws, the proper legal standard to apply to people with repeat drug convictions who are later caught with firearms.

Justice Samuel Alito wrote for the majority, joined by Chief Justice John Roberts and Justices Clarence Thomas, Sonia Sotomayor, Brett Kavanaugh and Amy Coney Barrett.

The 1984 "three strikes" law mandates a 15-year sentence for being a felon in possession of a firearm if the defendant has been previously convicted of three violent felonies or "serious drug offenses," and the case dealt with when that mandatory minimum sentence should be applied when it comes to drug crimes.

The court ruling was a loss for Justin Rashaad Brown and Eugene Jackson, who were each convicted of felony drug offenses and later prosecuted for gun violations. They had asked the high court to overturn decisions by three-judge panels of the Third and Eleventh circuits, respectively, that upheld their 15-year minimum sentences under the ACCA.

The justices reviewed their consolidated cases in mulling whether a "serious drug offense" under the act reflects federal controlled-substance schedules at the time of a defendant's prior state crime, the time of the federal offense for which they are being sentenced, or the time of federal sentencing.

Pointing to previous cases, Justice Alito wrote that the ACCA "requires sentencing courts to examine the law as it was when the defendant violated it, even if that law is subsequently amended."

Justice Ketanji Brown Jackson wrote the dissent, joined by Justice Elena Kagan, and in part by Justice Neil Gorsuch.

Justice Jackson wrote that the relevant text of the act "establishes that courts should apply the drug schedules in effect at the time of the federal firearms offense that triggers ACCA's potential application."

"Nothing else — not precedent, context or purpose — requires a different result," she wrote.

Circuit courts have struggled to determine which legal standard to apply to ACCA cases, creating a three-way split among the appellate courts.

Brown and Jackson argued they were wrongly subjected to tougher sentences after courts considered their criminal records under more restrictive state laws instead of federal laws in place at the time of their sentencing for the firearm charges.

Brown claimed he was penalized in Pennsylvania for previous state law crimes involving marijuana, even though the federal definition of marijuana had changed by the time he was sentenced for the firearm possession charge. Jackson said a Florida judge punished him for state law convictions involving the cocaine analog ioflupane, even though the federal government delisted the drug as a Schedule II substance.

They said the ACCA incorporates the controlled substance list in effect either at the time of the federal gun offense or when the defendant is sentenced for the federal gun offense.

The U.S. Department of Justice contended that the sentence should reflect federal drug schedules that were in effect when a past drug offense occurred.

The majority found that "precedent and statutory context show that the government's interpretation is correct." The government's interpretation "also best fulfills ACCA's statutory objectives" of imposing higher punishments on defendants deemed especially dangerous when in possession of a firearm, the opinion stated.

Under the ACCA, a "serious drug offense" is one that carries a maximum of at least a 10-year prison sentence.  

"A prior drug conviction for an offense punishable by 10 years' imprisonment augurs a risk of future dangerousness even if the drug is no longer considered dangerous," Justice Alito wrote. "That is because the conviction reveals that the defendant previously engaged in illegal conduct that created a dangerous risk of violence, either with law enforcement or with others operating in the same illegal field. If left at large, such defendants present a serious risk to public safety."

In the dissenting opinion, Justice Jackson wrote that the definition of a "serious drug offense" in the ACCA "cross-references the highly mutable federal drug schedules." And the definition uses the present tense, she wrote, further bolstering "the conclusion that Congress was consciously incorporating the annual updates that the federal drug schedules embody."

"If Congress had wanted to reference a past version of the drug schedules, it easily could have indicated as much in the text of ACCA," the dissent states. "But Congress used the present tense instead, directing sentencing courts to look to the meaning of 'controlled substance' in effect when a defendant commits the federal crime requiring ACCA's application, not at some previous point in time."

Brown is represented by Jeffrey T. Green of Sidley Austin LLP.

Jackson is represented by Andrew Lee Adler of the Federal Public Defender's Office for the Southern District of Florida.

The U.S. government is represented by Austin Raynor, assistant to Solicitor General Elizabeth B. Prelogar of the U.S. Department of Justice.

The cases are Justin Rashaad Brown, Petitioner v. United States, case number 22-6389, and Eugene Jackson, Petitioner v. United States, case number 22-6640, both in the Supreme Court of the United States.

--Additional reporting by Marco Poggio, Jeff Overley and Katie Buehler. Editing by Robert Rudinger.

Update: This article has been updated with additional details.