In the case of Hennessy v. Richardson Drug Company in 1902, the U.S Supreme Court ruled on a dispute involving patent infringement. The plaintiff, Hennessy, claimed that Richardson Drug Company had infringed upon his patented process for producing quinine sulphate by using an alternative method which achieved similar results but used different chemicals and processes. The defendant argued that their method was sufficiently distinct from Hennessy's patent to avoid infringement. The court sided with the defendant, ruling that while both methods produced similar end products (quinine sulphate), they were fundamentally different in terms of procedure and chemical usage; therefore no patent infringement occurred.

In the dissenting opinion for Hennessy v. Richardson Drug Company, it was argued that the majority's decision to uphold a Louisiana law requiring foreign corporations to appoint an agent within the state as a condition of doing business there infringed upon interstate commerce rights. The dissent contended that this requirement imposed undue burdens on out-of-state companies and effectively discriminated against them in favor of local businesses. It further asserted that such laws could lead to protectionist measures by states, which would undermine national economic unity and violate constitutional principles governing interstate commerce. Therefore, according to this view, the Louisiana law should have been struck down as unconstitutional.