The U.S. Supreme Court case West Lynn Creamery, Inc., et al. v. Jonathan Healy, Commissioner of Massachusetts Department of Food and Agriculture in 1993 involved a challenge to the constitutionality of a pricing order issued by the Massachusetts Department of Food and Agriculture that imposed an assessment on all milk sold by dealers to retailers in the state, regardless if it was produced within or outside Massachusetts. The proceeds were then distributed among local dairy farmers as subsidy payments which disproportionately benefited those within the state compared to out-of-state producers who also had to pay into this system but received little benefit from it. West Lynn Creamery and other out-of-state dairy processors argued that this scheme violated the Commerce Clause because it discriminated against interstate commerce while favoring local businesses with subsidies funded largely by their competitors from other states. In its decision, the Supreme Court agreed with West Lynn Creamery's argument stating that although states have some authority over their own economies under federalism principles, they cannot use regulatory measures designed primarily for economic protectionism at expense of interstate commerce.

In the dissenting opinion for West Lynn Creamery, Inc. v. Jonathan Healy, Justice Scalia argued that the Massachusetts pricing order did not violate the Commerce Clause of the U.S Constitution as it treated in-state and out-of-state milk producers equally. The majority ruled that this law was discriminatory because it used a tax on all milk sales to subsidize only Massachusetts dairy farmers, thus disadvantaging out-of-state competitors. However, Scalia contended that there was no discrimination since both local and interstate commerce were taxed at an equal rate per gallon of milk sold within Massachusetts; therefore, he saw no constitutional violation. Additionally, he pointed out that if every state followed suit with similar laws favoring their own industries through non-discriminatory taxes or fees coupled with subsidies for local businesses - which is what states have always done - then there would be no harm to overall national commerce.