A federal judge on Wednesday permanently barred President Donald Trump’s administration from implementing most of his first executive order on elections, part of which sought to require people to show documentary proof of citizenship when they register to vote.

The ruling by U.S. District Court Judge Denise Casper in Boston effectively converts a preliminary injunction she issued a year ago, in which she temporarily blocked many of Trump’s efforts to overhaul elections, into a permanent ban.

Casper rejected the administration’s argument that the lawsuit to block the changes brought by Democratic state attorneys general was premature because the rules had yet to be implemented. Instead, she agreed that the Constitution gives states and Congress the authority to regulate elections, and that Trump’s requirements violated the separation of powers.

The Constitution “does not grant the President any specific powers over elections,” she wrote.

Among other proposed changes, Trump’s order would have required people to provide documentary proof of citizenship when registering to vote, prevented mail ballots from being counted if they arrive after Election Day, even if they were postmarked by then, and punished states that failed to comply by withholding certain federal money.

It was the latest in a string of rulings against the elections executive order Trump signed just months after taking office for his second term. He has since signed another executive order on elections, seeking to create a national voter list and limit mail balloting. That directive also faces multiple legal challenges.