In attempting to explain state support of public higher education, this study develops a theory-driven, comprehensive conceptualization of the state political system within a larger theoretical framework that consists of state economic and demographic factors and higher education system attributes. Furthermore, although the higher education policy and finance literature has largely ignored the impact of interest groups on state policy and state support of higher education, they play a central role in the model presented here. The inclusion of politics in the explanatory model results in a more robust and pragmatically useful model. (Contains 2 figures, 3 tables and 5 notes.)