Rule 403 allows the exclusion of relevant evidence on the grounds of "unfair prejudice." Unfair prejudice to a criminal defendant means the danger that the jury will "generaliza defendant's earlier bad act into bad character and taking that as raising the odds that he did the later bad act now charged (or worse, as calling for preventive conviction even if he should happen to be innocent momentarily)." [https://www.law.cornell.edu/rules/fre/rules.htm#Rule404 Rule 404(b) addresses this danger directly, to be sure; however, prior convictions also present a danger of unfair prejudice and are thus subject to the Rule 403 balancing test.