Activists and scholars have often complained that the American criminal justice system makes choices about criminalization and sentences based on nefarious reasons. For instance, critics have claimed that criminalization and sentencing decisions are made to provide cheap prison labor to the government or private industry, to boost the private prison industry, to offer employment in rural communities in the form of jobs managing correctional facilities, or to empower police to harass undesirables and remove them from public spaces. These accusations are very alarming, and the evidence may not confirm activists’ worst suspicions. But, supposing the extraordinary evidence could be adduced, what difference would it make in a court of law? While most can agree that officials act wrongly if motivated by these concerns, it is less clear whether such officials act illegally. Does constitutional law disclose any legal ground for opposing action taken for these nefarious purposes? This Article outlines a strategy that courts might adopt for finding that some governmental purposes are, constitutionally speaking, forbidden purposes. Purpose-based arguments for invalidating government action are not entirely new. Rational basis review, familiar from the Equal Protection and Substantive Due Process contexts, sometimes requires courts to determine whether governmental action advances legitimate purposes. However, such scrutiny lacks general elucidation, and few have endeavored to elaborate how this would work specifically in the criminal sphere. This Article is a first attempt to develop a method for distinguishing the legitimate from the forbidden purposes in criminal law and beyond. On the proposed framework, courts would consider the constitutive rules of liberal legal systems, that is, those rules that both define and govern liberal legal systems. The set of constitutive rules will limit the state’s pursuit of certain aims, and those foreclosed options are, on the proposed framework, forbidden purposes under rationality review.

活动人士和学者经常抱怨美国刑事司法系统基于邪恶的理由做出定罪和量刑的选择。例如，批评者声称，定罪和量刑决定是为了向政府或私营企业提供廉价监狱劳动力，促进私营监狱产业发展，以管理惩教设施的形式为农村社区提供就业机会，或者赋予权力。警察骚扰不受欢迎的人并将他们驱逐出公共场所。这些指控非常令人震惊，而且证据可能无法证实活动人士最严重的怀疑。但是，假设可以举出非同寻常的证据，那么在法庭上会有什么不同呢？虽然大多数人都同意，如果官员出于这些担忧，就会采取错误的行动，但尚不清楚这些官员的行为是否违法。宪法是否公开了反对为这些邪恶目的而采取的行动的任何法律依据？本文概述了法院可能采取的策略，以认定某些政府目的从宪法上讲是禁止的目的。基于目的的主张政府行为无效的论点并不是全新的。理性基础审查，类似于平等保护和实质性正当程序背景，有时要求法院确定政府行为是否促进合法目的。然而，这种审查缺乏一般性的说明，而且很少有人努力详细说明这在犯罪领域如何具体发挥作用。本文首次尝试制定一种方法来区分刑法及其他领域的合法目的和禁止目的。在拟议的框架中，法院将考虑自由主义法律体系的构成规则，即定义和管辖自由主义法律体系的规则。这套宪法规则将限制国家对某些目标的追求，而在拟议的框架中，那些被排除的选择是合理性审查中禁止的目的。