BOSTON — An Obama-appointed federal judge in Boston has handed President Donald Trump's election-integrity agenda its most consequential defeat yet, permanently striking down the heart of his executive order on federal voting — including a requirement that would have forced new registrants to prove they are American citizens.

U.S. District Chief Judge Denise Casper, who has emerged in 2026 as one of the most reliable judicial obstacles to the second Trump administration, converted a year-old preliminary injunction into a sweeping permanent ban on Wednesday. In her ruling, she declared that the Constitution "does not grant the President any specific powers over elections" — language quickly seized on by Democratic state attorneys general as a vindication and by conservatives as confirmation that the federal bench is again being used to override the White House's policy agenda.

The decision was first flagged on X by Fox News national correspondent Bill Melugin, who noted that the Department of Justice is expected to appeal the order swiftly.

The permanent injunction kneecaps three pillars of Trump's first election executive order:

In effect, Casper has restored the pre-Trump status quo on every meaningful piece of the order, leaving the administration with little to enforce and an appellate fight as its only path forward.

She also rejected the administration's argument that the Democratic AG-led suit was premature because the new requirements had not yet kicked in — a ruling that signals other judges may follow her lead in greenlighting pre-enforcement challenges to Trump executive orders going forward.

Casper, the first black woman to sit on the federal bench in Massachusetts, was elevated to chief judge of the District of Massachusetts in 2025. A Wesleyan and Harvard Law graduate, she was nominated by President Barack Obama in 2010 and previously served as an assistant U.S. attorney in Boston and a deputy district attorney in Middlesex County.

This is not her first headline-grabbing collision with the Trump White House. Earlier in 2026, she blocked a separate Trump effort to claw back Inflation Reduction Act climate grants, drawing fierce criticism from conservative legal commentators who accuse her of legislating from the bench in apparent service of progressive policy outcomes.

The lawsuit was brought by a coalition of Democratic state attorneys general, with New York's Letitia James — a longtime Trump antagonist — among the most prominent plaintiffs named in the proceedings. Their argument tracked Casper's eventual reasoning: that under the Constitution's Elections Clause, the power to set the time, place, and manner of federal elections rests with the states and Congress, not the executive branch.

The proof-of-citizenship provision was, politically, the most explosive piece of Trump's order. Polling has consistently shown lopsided public support for requiring documentary proof of citizenship to register to vote, and the administration framed the requirement as a baseline safeguard against non-citizen voting in federal elections.

Casper's ruling all but ensures that the issue — and the broader fight over who controls American election rules — now heads to the First Circuit Court of Appeals, and likely to the Supreme Court after that. Until then, the practical effect is that no federal proof-of-citizenship requirement will be enforced this cycle, and state laws on mail-ballot receipt deadlines will continue to govern.

For the Trump administration, the message from Boston is clear: getting election-integrity policy through Congress, rather than through a presidential pen, may be the only path that survives the courts.