Discovery obligations apply to court-martial motions practice, for example when there is to be a suppression hearing.

The government has a mandatory duty to disclose evidence in its possession that is favorable to the defense, "either because it was exculpatory or of impeachment value . . . ." . The government breaches the duty established by Brady v. Maryland, 373 U.S. 83 (1963), and its progeny, including Giglio v. United States, 405 U.S. 150 (1972), when it withholds such evidence, either willfully or inadvertently, and the withheld evidence is found to be "material." Id. In the context of non-disclosed impeachment evidence, materiality is assessed in terms of whether the reliability of the witness in question may well be determinative of the outcome of the proceedings. See Pennsylvania v. Ritchie, 480 U.S. 39 (1987). That is, the evidence must be such that "there is a reasonable probability that, had the evidence been disclosed to the defense, the result of the proceeding would have been different." (quoting United States v. Bagley, 473 U.S. 667, 682 (1985)). Stated otherwise, "the relevant question is: ‘when viewed as a whole and in light of the substance of the prosecution’s case, did the government’s failure to provide . . . [the] Brady impeachment evidence to the defense . . . lead to an untrustworthy [result]. . . ." (some citations omitted).

United States v. Best, No._________, 2009 U.S. Dist. LEXIS 119802, at *19–20 (M.D. Pa. Dec. 23, 2009).

“Mandatory duty” is what I usually refer to as a self-executing duty that does not require the defense to make a discovery request.  Trial counsel at court-martial sometimes state that they didn’t (or don’t) have to give “Brady” discovery until there’s a defense request, or until the MJ has arraigned and docketed.  Not so.  Also, it is my view that the prosecution has an affirmative obligation to seek out Brady-plus discovery.

Best stands for the proposition that Brady and impeachment evidence should be disclosed prior to a suppression hearing if the information relates to a prosecution witness who will be testifying.