The Attorney General has new issued guidance memorandums to U.S. Attorneys on criminal discovery. Memos to United States Attorneys: Establishing Guidance for Prosecutors Regarding Criminal Discovery, The Justice Blog, Jan. 4, 2010. This post is on the DOJ's own blog and links to the three memos.
One of the guidance memos explains:
There are times when providing discovery broader than that required even by current Department policy serves the interests of justice. Providing broad and early discovery often promotes the truth-seeking mission of the Department and fosters a speedy resolution of a case. On the other hand, there are times when countervailing considerations counsel against broad and early disclosure. For these reasons, the discovery guidance is intended to assure that prosecutors make considered decisions about whether to disclose information beyond the requirements of law and policy and when to disclose it.