Supreme Court Justice Elena Kagan issued a majority opinion on Friday that will make it more difficult for criminal defendants to be eligible for relief under the First Step Act of 2018, a tough-on-crime decision that made for an unusual ideological split among the jurists.

The 6-3 opinion by Kagan marked a win for the Biden administration over its dispute over the “safety valve” relief in the 2018 law, which allows judges to ignore mandatory minimum sentences based on a drug offender’s criminal history. The crux of the issue in Pulsifer v. United States dealt with lower courts disagreeing about the word “and” as it is used in the bipartisan 2018 criminal overhaul and whether it indeed means “and” or whether it means “or.”