A federal judge in Washington, D.C., on Friday halted key sections of President Donald Trump’s sweeping executive order purporting to unilaterally change the rules regarding how federal elections are run, finding that the plaintiffs in the case were “substantially likely to prevail” on the merits.

In a 120-page order, U.S. District Judge Colleen Kollar-Kotelly issued a preliminary injunction blocking the president’s measure that would require amending the national voter registration form to require proof of U.S. citizenship as well as a provision ordering federal agencies to “assess the citizenship” of individuals who receive public assistance before they are provided a voter registration form.

Kollar-Kotelly, an appointee of President Bill Clinton, wrote that allowing those measures to be implemented would cause “irreparable harm” to the plaintiffs and “would not be in the public interest.”

“Our Constitution entrusts Congress and the States — not the President — with the authority to regulate federal elections,” the order states. “Consistent with that allocation of power, Congress is currently debating legislation that would effect many of the changes the President purports to order. And no statutory delegation of authority to the Executive Branch permits the President to short-circuit Congress’s deliberative process by executive order.”

The court noted that the legislation in Congress is the Safeguard American Voter Eligibility [SAVE] Act, a Republican-backed measure critics have said could potentially disenfranchise millions of eligible voters. Many provisions of the SAVE Act are encompassed by Trump’s executive order.