Article IV imposes prohibitions on interstate discrimination that are central to our status as a single nation, yet the Constitution also grants Congress broad power over interstate relations. This raises questions with respect to the scope of Congress's power over interstate relations, what is sometimes referred to as the horizontal dimension of federalism. In particular, does Congress have the power to authorize states to engage in conduct that otherwise would violate Article IV? These questions are of growing practical relevance, given recently enacted or proposed measures--the Defense of Marriage Act (DOMA) being the most prominent example--in which Congress has sanctioned interstate discrimination and other state measures seemingly at odds with fundamental precepts of horizontal federalism. These questions also are significant on a more conceptual level, as they force clarification of the proper relationship between Congress and the Supreme Court in horizontal federalism disputes.
This Article contends that the Constitution grants Congress expansive authority to structure interstate relationships and that in wielding this interstate authority Congress is not limited by judicial interpretations of Article IV. Rather than constituting unalterable demands of union, the antidiscrimination provisions of Article IV are best understood, like the dormant commerce clause, as constitutional default rules. These provisions are judicially enforceable against the states, but their enforceability is contingent on the absence of congressionally authorized discrimination. Congress's power to authorize discrimination has limits; however, those limits derive not from Article IV or principles of federalism, but instead from the Fourteenth Amendment.
Constitutional text, precedent, normative and functional concerns, and history all support such congressional primacy in interstate relations. Ultimately, however, the basis for broad congressional interstate authority is constitutional structure. Most of the Article is devoted to a close analysis of these standard sources of constitutional meaning to determine the appropriate parameters of the congressional role in interstate relations. The Article closes with an examination of the practical implications of such a broad view of Congress's powers, assessing the constitutionality of DOMA and the recently proposed Child Interstate Abortion Notification Act.
Consider three potential federal statutes:
* Congress authorizes states to refuse to recognize laws and judgments of other states that relate to same-sex marriage.
* Congress authorizes states to impose residency requirements as a condition of engaging in certain economic activities within a state, such as the provision of legal services.
* Congress imposes civil and criminal penalties on anyone who knowingly assists a minor to obtain an out-of-state abortion without complying with the parental notification requirements of the state in which the minor resides.
Each of these statutes authorizes interstate discrimination in some form. Moreover, absent such authorization, each form of discrimination is of dubious constitutionality. Under current case law, state legislation refusing to recognize other states' judgments or requiring residency as a condition of occupational licensure plainly contravenes Article IV of the Constitution. (1) Collectively, therefore, these hypothetical measures raise questions with respect to the scope of congressional power over interstate relations in general and Article IV in particular.
Those questions are of increasing practical importance. Conjuring up these statutes requires no great feat of legal imagination. The first, of course, is already enacted law, in the form of Section 2 of the 1996 Defense of Marriage Act (DOMA). (2) The third may soon become law; it mirrors Section 2 of the Child Interstate Abortion Notification Act (CIANA), which the House passed in 2005 and which the Senate adopted in the form of the Child Custody Protection Act (CCPA) in 2006. …