The White House is to preserve copies of all its e-mails, which Bush administration lawyers had argued strongly against.
U.S. District Judge Henry Kennedy directed the Executive Office of the President to safeguard the material in response to two lawsuits that seek to determine whether the White House has destroyed e-mails in violation of federal law.
The White House is seeking dismissal of the lawsuits brought by private groups, Citizens for Responsibility and Ethics in Government and the National Security Archive.
The organizations allege that 5 million White House e-mails have disappeared. The court order issued by Kennedy, an appointee of former President Bill Clinton, is directed at maintaining backup tapes that contain copies of White House e-mails.
The Federal Records Act details strict standards prohibiting the destruction of government documents, including electronic messages, unless first approved by the archivist of the United States.
Justice Department lawyers had urged the courts to accept a proposed White House declaration promising to preserve all backup tapes.
"The judge decided that wasn't enough," said Anne Weismann, an attorney for CREW, which has gone to court over secrecy issues involving the President George W. Bush's administration and has pursued ethical cases involving Republicans in Congress.
The judge's order "should stop any future destruction of e-mails, but the White House stopped archiving its e-mail in 2003, and we don't know if some backup tapes for those e-mails were already taped over before we went to court. It's a mystery," said Meredith Fuchs, a lawyer for the National Security Archive.
CREW and the National Security Archive are seeking to force the White House to explain immediately in court what happened to its e-mail, an issue that first surfaced nearly two years ago in the leak probe of Bush administration officials who disclosed Valerie Plame's secret CIA identity to reporters.
Special Counsel Patrick Fitzgerald revealed early in 2006 that relevant e-mails could be missing because of an archiving problem at the White House.
The White House has provided little public information about the matter, saying that some e-mails may not have been automatically archived on a computer server for the Executive Office of the President, and the e-mails may have been preserved on backup tapes.
The White House has said its Office of Administration is looking into whether e-mails were not automatically archived, and if there is a problem, the necessary action will be taken to address it.