Months before the Bush administration ends, historians and open-government advocates are concerned that Vice President Cheney, who has long bristled at requirements to disclose his records, will destroy or withhold key documents that illustrate his role in forming U.S. policy for the past 7 1/2 years.

In a preemptive move, several of them have agreed to join the advocacy group Citizens for Responsibility and Ethics in Washington in asking a federal judge to declare that Cheney's records are covered by the Presidential Records Act of 1978 and cannot be destroyed, taken or withheld without proper review.

The group expects to file the lawsuit today in the U.S. District Court for the District of Columbia. It will name Cheney, the executive offices of the president and vice president, and the National Archives and chief archivist Allen Weinstein as defendants.