A federal appeals court did not accept the Trump administration’s attempt to implement an executive order regarding new restrictions on mail-in voting and prevented parts of the order from being carried out in 23 states.

The case concerns Trump’s executive order to change mail-in voting regulations; an action his administration justified as being aimed at verifying voters’ eligibility and preventing ineligible people from voting. Opponents of the order say that the implementation of election laws under the Constitution is the responsibility of the states and Congress, not the president.

The U.S. Court of Appeals for the First Circuit, while upholding the lower court’s ruling, did not allow these restrictions to be enforced in the states of the plaintiffs.

However, the final status of this order is still unclear, and the Trump administration could pursue its request at the U.S. Supreme Court.