A federal judge on Monday overturned a key part of an executive order that restricts access to presidential records, handing researchers and advocacy groups a limited victory in their fight for access to the records. President Bush issued the order in 2001, prompting a lawsuit by a group that includes the American Historical Association and the nonprofit National Security Coalition.

In her ruling, U.S. District Judge Colleen Kollar-Kotelly said that the archivist of the United States’ reliance on one section of the order to determine how long to delay the release of presidential papers was “arbitrary, capricious, an abuse of discretion, and not in accordance with law.” And she barred the archivist from continuing to rely on that section.

But Judge Kollar-Kotelly stopped short of declaring the order itself unconstitutional or setting limits on the authority of former presidents and vice presidents and their heirs to decide when, or whether, to release their records.

The National Coalition for History, a historians’ advocacy group, called the ruling “a partial but significant” victory for historians and researchers. But the plaintiffs were disappointed that the ruling did not go further.

“The court is enforcing procedural standards, but has avoided the hard questions about the role former presidents, former vice presidents, and their heirs can play when it comes to disclosure of presidential records,” said Meredith Fuchs, general counsel of the National Security Archive, a plaintiff. “Unless the executive order is reversed or withdrawn, decisions about the release of records from this administration may ultimately be made by the Bush daughters.” Legislation to overturn the order remains blocked in the Senate. —Jennifer Howard