The Supreme Court on Monday threw out an Arizona law that required people to prove they were citizens before they could use a new federal registration system meant to make signing up to vote easier.

In a 7-2 vote, the court ruled the Arizona law was trumped by the federal “motor voter” registration law.

The decision split conservatives on the High Court, with Associate Justice Antonin Scalia writing the opinion for the majority and fellow conservative Justices Samuel Alito and Clarence Thomas dissenting.

The court’s liberal wing sided with Scalia, as did Chief Justice John Roberts and Justice Anthony Kennedy.