In the 1980s and early 1990s, Massachusetts dairy farms began to lose their share of the overall dairy market due to lower prices of their competitor producers in other states. In response to the downsizing of the Massachusetts dairy market, the state created a Special Commission to investigate solutions to this problem. Healy (defendant), head of the Special Commission, recommended that Massachusetts impose a tax on all fluid milk sold to Massachusetts retailers by dealers. The tax would then be used to subsidize the efforts of Massachusetts’s dairy farmers to help them compete in the national milk market. West Lynn Creamery, Inc. (plaintiff), an out-of-state milk dealer, was taxed. West Lynn Creamery challenged the Massachusetts statute in superior court on the grounds that it impermissibly discriminated against interstate commerce. The court denied relief, and the state supreme court affirmed. The United States Supreme Court granted certiorari.