When will a federal court's decision not to admit evidence at trial be overturned?

A district court has "wide discretion" in determining whether to admit evidence at trial, United States v. Carboni, 204 F.3d 39, 44 (2d Cir. 2000), and its decision will be overturned only when "arbitrary or irrational," United States v. Han, 230 F.3d 560, 564 (2d Cir. 2000). We also review a district court's decision not to compel the government to grant use immunity to witnesses for abuse of discretion, although we "review the court's factual findings about government actions and motive for clear error." United States v. Ferguson, 676 F.3d 260, 291 (2d Cir. 2011). Nonetheless, "'[t]he situations in which the United States is required to grant statutory immunity to a defense witness are few and exceptional.' So few and exceptional are they that, in the . . . thirty years since establishing a test for when immunity must be granted, we

Page 3

have yet to reverse a failure to immunize." Id. (quoting United States v. Praetorius, 622 F.2d 1054, 1064 (2d Cir. 1979)). Claims not raised before the district court are reviewed for plain error. See United States v. Marcus, 560 U.S. 258, 262 (2010).