Wynne’s implications extend significantly beyond the particular facts of that case. The five justice Wynne majority used that case to make a major statement about the dormant Commerce Clause. In many respects, Wynne is an enigma which perpetuates an inherent problem of the Court’s dormant Commerce Clause doctrine: The Court declares some, ill-defined taxes as unconstitutionally discriminatory because such taxes encourage in-state investment while other, economically equivalent taxes and government programs which similarly encourage intrastate economic activity are apparently acceptable under the dormant Commerce Clause.
Wynne is more important than the immediate situation it addresses and will have consequences beyond the immediate circumstances it addresses. A decision as enigmatic as it is important, Wynne raises as many questions as it answers. Among these are the continuing viability (or not) of external consistency and apportionment, concepts which have been central to the Court’s formulation of the dormant Commerce Clause. Wynne also undermines the Court’s traditional tolerance of the double state income taxation of dual residents since such double taxation can encourage a dual resident to undertake single-taxed in-state economic activity rather than make investments subject to such double taxation.