The Wabash Railway Company et al. v. Barclay et al., 1929 case revolved around the issue of whether a state could regulate rates for intrastate portions of interstate shipments, which was challenged by the railway company as an infringement on federal authority over interstate commerce. The Supreme Court ruled in favor of Wabash Railway Company, holding that states did not have the power to regulate rates for any part of an interstate shipment, even if some parts were within their borders. This decision reinforced and expanded upon previous rulings limiting state regulation over interstate commerce and underscored the supremacy of federal law in such matters.

The dissenting opinion in the WABASH RAILWAY COMPANY et al. v. BARCLAY et al., case argued that the majority's decision to uphold a Missouri law requiring railroads to maintain certain types of fencing was an overreach of state power and violated principles of federalism. The dissenters believed that this ruling interfered with interstate commerce, as it imposed burdensome regulations on railroad companies operating across state lines, potentially disrupting their operations and causing economic harm. They also contended that such matters should be left up to federal regulation rather than individual states' laws due to the national nature of railway transportation systems.