Grant Christensen has published “Article IV and Indian Tribes” in the Iowa Law Review (PDF). Here is the abstract:

Unlike the first three articles of the Constitution which create the three branches of the federal government and articulate their limited powers, Article IV establishes a set of rules to police the actions of states and knit them together into a single union. Notably absent from Article IV is any mention of the tribal sovereign. Concomitantly, there has been no comprehensive academic discussion addressing how the tribal sovereign complicates the purposes of Article IV. This piece advances a completely new understanding of Article IV and its implications in federal Indian law. It argues that where Article IV advances rights to individual citizens (i.e., a citizen’s right to enforce a court judgment or their claim to the protection of the Privileges and Immunities Clause) then states may not use an individual’s connection to any tribal sovereign as an excuse to deny them the protections of those rights. In contrast, where Article IV speaks to rules designed to ensure states treat each other respectfully (i.e., requests for extradition, claims under the Equal Footing Doctrine, or any attempt to enforce the Guarantee Clause) then Article IV’s rules do not permit states to abridge, abrogate, modify, or erode the inherent rights of tribal nations. As the Court has recently opined, tribal governments themselves were absent from the Constitutional Convention and so constitutional limitations on the inherent powers of state sovereigns do not extend to tribal governments.