Felix Frankfurter

“ The mere fact that the same number of dollars could have been exacted by the State in a constitutional way cannot legalize every tax, 'as though the ad valorem rate had been increased.' Because a State could obtain twice the amount of revenue that it gets from an interstate business by increasing the ad valorem rate does not constitutionally justify a tax which, by virtue of a stipulation having the force of truth is not referable to any protection which the State accords. ”

“ By this statement the petitioner clearly asserted that insofar as Mississippi has power to tax this interstate business for the protection accorded the 'local incidents' of that business, the taxes levied by the State through its local taxing authorities exhausted the power. To tax beyond that is bald tax on the privilege of doing interstate commerce. ”

“ A State legislature may be ready to levy a tax for the privilege of doing interstate business within the State-as legislatures have again and again attempted to do-and not be prepared to increase outright the ad valorem rate. ”