Uniform Throughout the United States: Limits on Taxing as Limits on Spending

The Constitution's requirement that federal taxation be "uniform throughout the United States" precludes explicit conditioning of federal taxation upon state political identity. That limitation upon taxation informs the Constitution's obverse requirement that federal spending be for the "common Defence and general Welfare" of the United States. A state's lawful policy choices are elements of its political identity. Conditions on federal spending which explicitly target elements of a state's political identity violate the Constitution's obverse requirements that taxation be uniform and that spending be common and general.