Evidence of Prior Assaults Improperly Admitted In Assault Case Where Self-Defense Claimed

US v. Commanche, -- F.3d --, 2009 WL 2581737 (10th Cir. 8/24/09) - defense victory! In assault resulting in serious bodily injury case, the district court improperly admitted under Fed.R.Evid. 404(b) bad acts evidence against the defendant. Self defense was the defense. After being attacked first, Mr. Commanche used a box cutter. He had two other aggravated battery convictions in which he used a sharp object. Gov't claimed other incidents showed defendant carried a box cutter knife as a weapon rather than a work tool. Court of Appeals concludes it is irrelevant to self-defense inquiry that a box cutter was used on other occasions and that the other acts evidence simply showed he was violent. Error likely had a substantial impact on trial outcome and was not harmless. District court plainly erred in permitting evidence under Fed.R.Evid. 609(a)(1) beyond simple fact of convictions of aggravated battery; gov't should not have presented evidence that the other crimes involved box cutters or similar weapons.