The U.S. Supreme Court on Monday ruled that district courts must look at defendants' rehabilitation and updated sentencing guidelines when considering a reduction of their sentences. 

With a 5-4 vote displaying an unlikely array of justices, the high court reversed a ruling by the U.S. Court of Appeals for the First Circuit that affirmed the 19-year sentence of Carlos Concepcion, a convicted Massachusetts crack cocaine dealer who sought to reduce his prison time after the passage of sentencing reforms.

Justice Sonia Sotomayor wrote in the majority opinion that federal trial courts must, except in the case of frivolous claims, look at a defendant's conduct and changes in the Federal Sentencing Guidelines since the original sentencing when considering reducing a sentence.

"It is only when Congress or the Constitution limits the scope of information that a district court may consider in deciding whether, and to what extent, to modify a sentence, that a district court's discretion to consider information is restrained," Justice Sotomayor said in the opinion, joined by Justices Stephen G. Breyer and Elena Kagan, as well as two justices from the court's conservative bloc, Clarence Thomas and Neil Gorsuch.

Monday's ruling addressed a deep and acknowledged split among courts of appeals as to the amount of discretion district courts have in reviewing sentences under the First Step Act of 2018, a bipartisan law that reduced mandatory minimum sentences for certain offenses.

The ruling largely settles the issue, giving district courts the power to look at a defendant's whole array of circumstances and new sentencing guidelines ushered by criminal justice reforms.

Citing several high court cases that established the district courts' ample discretion in the sentencing process, Justice Sotomayor said the First Step Act does not tie judges' hands when they consider those factors, but rather mandates that they consider them.

"Congress in the First Step Act simply did not contravene this well-established sentencing practice. Nothing in the text and structure of the First Step Act expressly, or even implicitly, overcomes the established tradition of district court's sentencing discretion," her opinion says.

But courts deciding a First Step Act motion do not have to accept the arguments by a defendant that evidence of rehabilitation or other changes in law warrant a sentence reduction or a prosecutor's view that evidence of violent behavior in prison supports denying relief, the opinion says.

"All that is required is for a district court to demonstrate that it has considered the arguments before it," and to explain their decisions, the opinion says.

Justice Brett Kavanaugh dissented in an opinion joined by Chief Justice John G. Roberts, Jr. and Justices Samuel Alito and Amy Coney Barrett.

"The Court today concludes that district courts in First Step Act sentence-modification proceedings may reduce sentences based not only on the changes to the crack-cocaine sentencing ranges, but also on other unrelated legal or factual changes that have occurred since the original sentencing," Justice Kavanaugh wrote. "I respectfully disagree." 

In essence, the minority opinion argues a First Step Act sentence modification is not a true resentencing proceeding, and as such the scope of information judges need to consider is much narrower.

A court deciding a motion for the resentencing under the First Step Act should only determine ​​what a defendant's sentence would have been if the lower crack cocaine sentencing ranges had been in effect at the time of the original sentencing, Kavanaugh wrote.

The majority's "disregard" for the First Step Act "will create significant and inexplicable sentencing inequities," the dissenting opinion says.

Concepcion pled guilty to distributing five or more grams of crack cocaine in 2007 and was sentenced in 2009 as a career offender, at a time when penalties for crack far exceeded those for powder cocaine.

In 2010, Congress passed the Fair Sentencing Act, which increased the amount of crack cocaine needed to trigger a 5- to 40-year sentencing range from 5 grams to 28 grams, and reduced the sentence disparity ratio between crack and powder cocaine offenses from 100-1 to 18-1. In 2011, the U.S. Sentencing Commission voted to apply the law retroactively.

Concepcion made three unsuccessful attempts to have his sentence lowered under the law. Then, in 2019, a year after the enactment of the First Step Act, Conception filed a pro-se motion for resentencing arguing that his sentencing range should have been roughly 15½ to 19½ years.

He later argued that he no longer qualified as a career offender under the law, and pointed to his drug treatment, pursuit of education and good behavior in prison as mitigating factors warranting a lower sentence.

But first the U.S. District Court for the District of Massachusetts, then a divided panel of the First Circuit, denied his motion, ruling that the trial court did not have to consider his new personal circumstances or take changes in sentencing laws into account.

Under the doctrine adopted by the First, Second, Sixth, Seventh, and Eighth circuits, district courts may or may not consider those variables, while only being required to adopt the revised maximum and minimum sentences for crack cocaine spelled out in the First Step Act.

The rule adopted by the Fifth, Ninth, and Eleventh circuits is more stringent: District courts are barred from considering any intervening case law or updated sentencing guidelines, and are not required to consider the personal circumstances of a prisoner during resentencing.

Over time, the circuit split resulted in deeply uneven sentences across the country. The doctrinal divide was also an entry ticket for Concepcion's case into the Supreme Court's docket.

Charles L. McCloud and Lisa Blatt of Williams & Connolly LLP, who argued on behalf of Concepcion before the high court in January, did not respond to a request for comment on the ruling. The U.S. Department of Justice declined to comment.

Concepcion is represented by Charles L. McCloud and Lisa Blatt of Williams & Connolly LLP.

The U.S. government is represented by Assistant to the Solicitor General Matthew Guarnieri.

The case is Concepcion v. United States, case number 20-1650, in the Supreme Court of the United States.

--Editing by Peter Rozovsky.