The decision is a setback for President Donald Trump, who has argued the requirement is needed to restore public confidence in elections. But the judge allowed other parts of Trump’s sweeping executive order on U.S. elections to go forward for now, including a directive to tighten mail ballot deadlines around the country.

The Trump administration cannot enforce parts of an EO requiring US election officials to assess if people who are registering to vote are citizens.

The blocked portion of the order would have changed the federal voter registration form to indicate proof of citizenship is required.