has the discretionary authority to allow the case in chief to proceed as the government suggests. See United States v. Dent, 984 F.2d 1453, 1463 (7th Cir.) (citing cases), cert. denied, 510 U.S. 858, 114 S.Ct. 169, 126 L.Ed.2d 129, and 510 U.S. 875, 114 S.Ct. 209, 126 L.Ed.2d 165 (1993); FED.R.EVID.