A federal judge on Friday blocked Donald Trump’s attempt to overhaul elections in the U.S., siding with a group of Democratic state attorneys general who challenged the effort as unconstitutional.

Judge Denise J. Casper of the U.S. District Court in Massachusetts said in Friday’s order that the states had a likelihood of success as to their legal challenges. “The Constitution does not grant the President any specific powers over elections,” Casper wrote.

Casper also noted that, when it comes to citizenship, “there is no dispute (nor could there be) that U.S. citizenship is required to vote in federal elections and the federal voter registration forms require attestation of citizenship.”