The Obama administration on Wednesday announced a new policy making it much more difficult for the government to claim that it is protecting state secrets when it hides details of sensitive national security strategies such as rendition and warrantless eavesdropping.

    The new policy requires agencies, including the intelligence community and the military, to convince the attorney general and a team of Justice Department lawyers that the release of sensitive information would present significant harm to "national defense or foreign relations." In the past, the claim that state secrets were at risk could be invoked with the approval of one official and by meeting a lower standard of proof that disclosure would be harmful.

    That claim was asserted dozens of times during the Bush administration, legal scholars said.