Donald Trump’s unilateral effort to reshape election processes is an attempt to “short-circuit Congress’s deliberative process by executive order,” a federal judge in Washington, D.C. wrote Thursday afternoon.

In a 120-page opinion, U.S. District Judge Colleen Kollar-Kotelly blocked the Trump administration from requiring proof of citizenship to register to vote and ordering that election officials “assess” the citizenship of anyone who receives public assistance before allowing them to register. She also barred the Election Assistance Commission from withholding federal funding from states that did not comply with the order.

“Our Constitution entrusts Congress and the States—not the President—with the authority to regulate federal elections,” she wrote. “No statutory delegation of authority to the Executive Branch permits the President to short-circuit Congress’s deliberative process by executive order.”

After Trump issued an executive order last month “preserving and protecting the integrity of American elections,” three separate lawsuits were filed in the D.C. federal court to challenge the policy, including lawsuits filed by the Democratic National Committee (with New York Sen. Charles Schumer and Rep. Hakeem Jeffries), the League of United Latin American Citizens and National Association for the Advancement of Colored People.

“These consolidated cases are about the separation of powers,” Judge Kollar-Kotelly wrote.

She concluded that Trump’s unilateral effort to reshape elections exceeds his own authority, noting that the Department of Justice “offered almost no defense of the President’s order.”

If Trump wishes to reform election processes, she wrote, Congress would be the appropriate branch to do so, adding Congress is “currently debating legislation that would effect many of the changes the President purports to order.”