The eventual disconnection between voters´ preferences and specific policies is of special concern in decentralized countries, where any policy initiative might be simultaneously seen either as an erosion or a reinforcement of selfrule. The aim of this paper is to apply this framework to the harmonization of the Spanish Inheritance and Gift Tax (IGT). We econometrically contrast whether citizens´ living in Autonomous Communities (ACs) that led a tax race to the bottom regarding this tax or in those that exert a greater taste for political autonomy are more likely to oppose a more nationally uniform tax than the rest of Spaniards. Empirically, we exploit data from the 2019 wave of the Institute for Fiscal Studies Fiscal Barometer. According to our main results, citizens living in low taxation ACs and citizens living in some more pro-self-rule regions are even more likely to favor harmonization. [ABSTRACT FROM AUTHOR]