"Dormant" Commerce Clause

The “Dormant Commerce Clause" refers to the prohibition, implicit in the Commerce Clause, against states passing legislation that discriminates against or excessively burdens interstate commerce. Of particular importance here, is the prevention of protectionist state policies that favor state citizens or businesses at the expense of non-citizens conducting business within that state. In West Lynn Creamery Inc. v. Healy, 512 U.S. 186 (1994), the Supreme Court struck down a Massachusetts state tax on milk products, as the tax impeded interstate commercial activity by discriminating against non-Massachusetts

https://supreme.justia.com/cases/federal/us/512/186/