American appellate courts have long resisted calls that they play a more robust role in the sentencing process, insisting that they must defer to what they characterize as the superior sentencing competence of trial judges. This position is unfortunate insofar as rigorous appellate review might advance uniformity and other rule-of-law values that are threatened by broad trial court discretion. This Article thus provides the first systematic critique of the appellate courts’ standard justifications for deferring to trial court sentencing decisions. For instance, these justifications are shown to be based on premises that are inconsistent with empirical research on cognition and decision making. Despite the shortcomings of the standard justifications, this Article suggests that there is a stronger argument for deference that is based on the trial judge’s background knowledge regarding the particular circumstances of the local community and courthouse. Even the potential benefits of localization, though, do not clearly outweigh the rule-of-law costs of appellate deference. Thus, this Article concludes with a proposal for a sliding-scale approach to deference that strengthens the appellate role, but also accommodates localization values in the cases in which they are most salient.