Stephen Mortellaro has posted this draft on SSRN (forthcoming Loyola Law Review).  Here is the abstract:

Congress strikes at the core of state sovereignty when it disenfranchises voters. Yet demands for national disenfranchisement laws have become pervasive since the 2016 election, and Congress has a ready model: a federal statute prohibiting noncitizens from voting in federal elections. Despite upending centuries of state control over voter qualifications, this statute remains unchallenged in court and unexamined in academia; its constitutionality has been assumed. This article challenges this assumption, arguing that the federal ban on noncitizen voting—along with every other voter qualification Congress may impose—unconstitutionally infringes state sovereignty.

Most voting rights scholarship focuses on the constitutional amendments that prevent disenfranchisement based on race, sex, wealth, and age. This article demonstrates how the Constitution limits the federal government even further. By tracing the history of the Elections Clause and analyzing contemporary election law jurisprudence, this article shows how Congress’s traditional sources of authority over federal elections do not empower it to impose substantive qualifications on voters. More fundamentally, examination of the text and history of the Voter Qualifications Clauses reveals that states possess an exclusive power to determine who is ineligible to vote. This analysis makes evident that all congressionally-imposed voter qualifications—even those that do not invidiously discriminate—cannot survive the constraints of American federalism.