Whether Massachusetts' assessment on all fluid milk sales, coupled with a distribution of all proceeds solely to Massachusetts dairy farmers, unconstitutionally discriminated against interstate commerce.
Holding
Yes. The integrated assessment-and-subsidy program was the practical equivalent of a protective tariff and violated the dormant Commerce Clause.
Reasoning
The dormant Commerce Clause prohibits economic protectionism: state measures designed to benefit in-state economic interests by burdening out-of-state competitors. A classic forbidden measure is a tariff that taxes imported goods while sparing comparable local goods, because it artificially shifts production toward the taxing State.
Although Massachusetts nominally assessed both local and out-of-state milk, the assessment's burden on Massachusetts producers was entirely offset—and more than offset—by payments reserved for them. Out-of-state milk bore the assessment without any corresponding producer subsidy. In practical operation, therefore, the order raised the relative cost of out-of-state milk and enabled higher-cost Massachusetts farmers to compete at the federally set minimum price.
The order's declared purpose and likely effect confirmed its protectionist character. It was designed to preserve Massachusetts farmers' market position against lower-cost out-of-state producers, thereby neutralizing the competitive advantage that producers possessed because of their location and lower costs. That is the same economic distortion condemned in cases such as Baldwin and Bacchus.