This Article discusses an important federal sentencing issue that has received little scholarly attention, despite affecting thousands of lives each year: the harsh prior conviction sentencing enhancements that defendants can receive in illegal re-entry cases—and only in illegal re-entry cases. The Sentencing Commission created the enhancement through a perfunctory process that radically altered illegal re-entry sentencing, shifting the focus at sentencing from the illegal re-entry offense to the status of the defendant’s worst prior conviction. The result is a scheme where the length of the sentence many illegal re-entry defendants receive hinges on what they previously did—sometimes many years ago—rather than on the conduct for which they are ostensibly being prosecuted. Despite the unusual nature of the enhancement, the Commission has never provided a justification for it, nor is one apparent. Moreover, the enhancement undercuts Congress’s goal of reducing unwarranted sentencing disparity and recommends sentences that are simply too harsh for illegal re-entry offenses. Although courts were previously powerless to do anything about the Commission’s indiscriminate decision making, that is no longer the case. Since the Supreme Court held in 2005 in United States v. Booker that the Guidelines are not mandatory, courts may now evaluate the soundness of the Guidelines themselves before imposing a sentence. Even a cursory examination of the prior conviction enhancements shows that they are unsound and should not be followed.