The U.S. Supreme Court on Friday threw out part of a tough federal criminal sentencing law for being overly broad in a ruling that backed a Minnesota white supremacist who challenged his sentence on a firearms crime.

The court ruled in favor of Samuel Johnson, who was given 15 years in prison for illegally possessing a firearm. The justices found on a 6-3 vote that a sentencing provision of the federal Armed Career Criminal Act is so expansive that it violated the U.S. Constitution's Fifth Amendment, which mandates due process under the law.

He will now be resentenced and will face a maximum sentence of 10 years. The ruling could also affect other inmates in similar situations.

The law imposes a minimum 15-year sentence when a defendant is convicted of possessing a firearm and has previously been convicted of at least three qualifying crimes, including violent felonies. The law outlines the crimes covered, including burglary and arson.

At issue in the case was an additional provision that says the law also applies to previous convictions that concern "conduct that presents a serious potential risk of physical injury to another."

Criminal defense lawyers said the phrase was too vague and violates the U.S. Constitution's Fifth Amendment, which mandates due process under the law. The Supreme Court has already had several cases in recent years touching upon what kind of conduct should be covered.

Johnson was hit with the additional sentence in 2012 when he pleaded guilty to one count of being a felon in possession of a firearm. He had previously been convicted of robbery on two occasions and possessing a short-barreled shotgun. Johnson's lawyers argued that merely possessing the shotgun should not count as a violent felony.

Johnson initially attracted the FBI's attention in 2010 due to his role with the National Socialist Movement, a white supremacist group.

(Reporting by Lawrence Hurley; Editing by Will Dunham)