Gene Mazo has posted this draft at SSRN (Seton Hall Law Review). Here is the abstract:

A scholarly literature has recently emerged to study, document, and measure the effects of New Jersey’s unique ballot bracketing system, colloquially known as the “county line,” which New Jersey’s party insiders and political machines have long used to determine the outcomes of the state’s primary elections. To date, this literature has examined how the “county line” works and what its empirical effects are, but it has thus far not adequately explained exactly why the “county line” system violates the U.S. Constitution. This Article fills this gap. Part I explores how New Jersey election law works to create the “county line” before surveying the different ways in which scholars have recently attempted to measure the “county line’s” empirical effects. Part II then proceeds to examine why the “county line” turns out to be so radically and vehemently repugnant to the Constitution. The Article looks at the recent litigation brought to challenge the “county line”—in the three cases of Conforti v. Hanlon, Mazo v. Durkin, and Kim v. Hanlon—and uses it to explore the rights-based balancing theories under which New Jersey’s “county line” ballot bracketing system violates the First and Fourteenth Amendments of the Constitution, as well as the structural non-balancing theories under which the “county line” violates the “by the People” provisions (found in Article I, Section 2 and the Seventeenth Amendment), the Qualifications Clauses, and the Elections Clause of the Constitution.