The U.S. Supreme Court case Chicago, Milwaukee & St. Paul Railway Company et al. v. Public Utilities Commission of the State of Idaho in 1926 revolved around a dispute between the railway company and the state commission over freight rates for intrastate transportation within Idaho. The railway company argued that these rates were discriminatory and violated their rights under both federal law and the Fourteenth Amendment to the Constitution, which guarantees equal protection under law. However, after careful consideration, it was ruled by Justice Sutherland that there was no violation as long as interstate commerce is not unduly burdened or discriminated against compared to intrastate commerce; thus upholding states' power to regulate local trade within their borders without interference from federal authorities unless it interferes with interstate commerce.

In the dissenting opinion for Chicago, Milwaukee & St. Paul Railway Company v. Public Utilities Commission of Idaho, Justice Stone disagreed with the majority's ruling that a state could not regulate interstate commerce rates even if they were intrastate in character. He argued that states should have regulatory power over railroads operating within their borders when federal regulation was absent or inadequate. In his view, this would prevent discrimination against local shippers and ensure fair competition among businesses using railroad services. He also believed it was necessary to protect consumers from excessive charges by monopolistic railroads which had no incentive to reduce prices due to lack of competition in many areas.