A federal judge in Boston on Thursday blocked implementation of President Donald Trump’s executive order aimed at tightening mail-in voting regulations, preventing it from taking effect ahead of November’s midterm elections. U.S. District Judge Indira Talwani sided with several Democrat-led states that argued the Republican president was unlawfully interfering with states’ constitutional authority to administer federal elections.

Trump signed the order on March 31 after years of calling for stricter mail-in voting rules and repeatedly claiming that his 2020 election loss resulted from widespread voter fraud. The U.S. Constitution assigns states the role of administering federal elections. Trump’s directive orders the Department of Homeland Security to compile and transmit to states a list of confirmed U.S. citizens eligible to vote, drawn from citizenship records and other federal databases.

The order also requires the U.S. Postal Service to deliver ballots only to voters on each state’s approved mail-in ballot list. USPS recently moved to implement the directive by issuing proposed rules requiring states to provide names and barcodes tied to their mail-in ballots. Additionally, the order directs the Justice Department to prioritize investigating and prosecuting state and local election officials who issue federal ballots to people deemed “not eligible” to vote.

Voting rights groups sued the administration alongside 23 states and the District of Columbia, arguing that Trump’s order is unconstitutional and that he lacks any legal authority to assert presidential power over election administration. The states alleged that allowing the order to stand would force them to rush to overhaul their election systems before November, causing chaos and likely disenfranchising eligible voters.

Talwani, an appointee of Democrat President Barack Obama, ruled after a different jurist — Trump-appointed U.S. District Judge Carl Nichols in Washington, D.C. — declined to issue a preliminary injunction in a related lawsuit brought by Democrats challenging Trump’s order. Nichols found that the Democrats’ request was premature because the order had yet to be implemented. That case is now being appealed.