At issue was whether South Dakota's preferential treatment of South Dakota residents in its sale of state-produced cement constituted a violation of the negative commerce clause. The Court ruled that South Dakota's preferential treatment of South Dakota residents in its sale of state-produced cement was not a violation of the negative commerce clause because South Dakota was acting as a market participant. The Supreme Court first promulgated the market participant exception to the negative commerce clause in
Hughes v. Alexandria Scrap Corp., in which Maryland offered a "bounty" for destroying abandoned Maryland automobiles but effectively limited receipt of the bounty to in-state residents. There, the Supreme Court upheld the Maryland law against Commerce Clause objections because the state of Maryland was acting as a participant in the market rather than as a market regulator. “Nothing in the purposes animating the Commerce Clause prohibits a State, in the absence of congressional action, from participating in the market and exercising the right to favor its own citizens over others.” Thus, while state laws that prefer intrastate commerce to interstate commerce for economic protectionism are ordinarily invalid per se, states when acting as market participants may engage in such discrimination. Here, South Dakota was acting as a market participant where Congress had not taken any regulatory action; thus, South Dakota could favor its citizens in the sale of state-produced cement over the citizens of other states. == References ==