Cir. 1988)); Aplee. Br. 21 (“[Elliott] asks this court to take the extraordinary step of exercising its supervisory power[ ] to suppress his statements.... ”). We recently emphasized our “circumspect approach to the exercise of the supervisory power.” United States v. Lilly, 810 F.3d 1205, 1219 (10th Cir. 2016); see also United States v. Payner, 447 U.S. 727, 734-35, 100 S.Ct. 2439, 65 L.Ed.2d 468 (1980) (noting Court’s “restrained application of the supervisory power,” which Court “applie[s] with some caution”). We don’t take lightly the assertion that a prosecutor has violated his ethical duties, and suppressing evidence is a stiff penalty. Thus, we typically demand full development of these issues in the district court. Cf. United States v. Thomas, 474 F.2d 110, 112 (10th Cir. 1973) (<HOLDING>). We lack the benefit of that development here.
holding that a trial courts determination of sanctions is committed to the trial courts dis cretion holding that where both the appellate and trial courts are reviewing the paper record  there is no reason for the appellate courts to defer to the trial courts finding holding that the supreme courts proper scope of review of a trial courts decision in a trial de novo of an assessment matter is whether the decision of the trial court was clearly erroneous holding that the problem is initially one for the trial courts holding that the proper review for the trial courts application of the law is de novo