An executive order from President Bush allowing an unlimited delay in the release of historical White House records is illegal and cannot be enforced, a federal judge ruled yesterday.

Judge Colleen Kollar-Kotelly said the Archivist of the United States, Allen Weinstein, is violating the law by obeying Mr. Bush’s 2001 order, which grants former presidents 90 days or more, and the sitting president an unlimited period, to review records for material that might be subject to executive privilege or other legal claims. “The Constitution does not require the Archivist to permit a former president an unlimited amount of time to review materials for privilege,” Judge Kollar-Kotelly wrote. She said Mr. Bush’s order seemed to nullify a provision in a 1978 law, the Presidential Records Act, which called for a shorter review in most circumstances and left the final decision on timing up to the archivist.

The judge sidestepped the issue of whether Mr. Bush acted lawfully when he granted the former vice presidents and the heirs of former presidents authority over release of some records.

The ruling came in response to a lawsuit from groups representing historians, journalists, authors, and others who regularly seek records from presidential libraries, which are run by the National Archives.