Abe Fortas

“ In determining whether a state tax imposes an impermissible burden on interstate commerce, the issue is whether the local activity which is made the nominal subject of the tax is 'such an integral part of the interstate process, the flow of commerce, that it cannot realistically be separated from it.' Michigan-Wisconsin Pipe Line Co. ”

“ If, for example, a license tax were imposed on the acts of engaging in soliciting orders or making deliveries, conflict with the Commerce Clause would be evident because these are minimal activities within a State without which there can be no interstate commerce. ”

“ Nor is the tax invalid as a discrimination against interstate commerce. Alabama's tax is levied equally upon all transient or traveling photographers whether their travel is interstate or entirely within the State. On the record before us, there is no basis for concluding that the $5 per week tax on transient out-of-state photographers is so disproportionate to the tax imposed on photographers with a fixed location [4] as to bear unfairly on the former. ”