Arthur Goldberg,
General Motors Corporation v. Washington…
“ A State therefore should not be enabled to put out-of-state producers and merchants at a disadvantage by imposing a tax to 'equalize' their costs with those of local businessmen who would otherwise suffer a competitive disadvantage because of the State's own taxation scheme. The disadvantage stemming from the wholesale sales tax was created by the State itself and therefore the fact that the State simultaneously imposes the same tax on interstate and intrastate transactions should not obscure the fact that interstate commerce is being burdened in order to protect the local market. ”
