In the case of Hopkins, Assessor, et al., v. Southern California Telephone Company et al., 1927, the Supreme Court ruled in favor of Southern California Telephone Company (SCTC). The dispute arose when SCTC challenged a tax assessment by Los Angeles County on its telephone lines and equipment. The county had assessed these properties at their full value while other personal property was being assessed at only 25% of its actual value. SCTC argued that this discrepancy violated the Fourteenth Amendment's Equal Protection Clause which requires equal treatment under law. The Supreme Court agreed with SCTC stating that such unequal taxation constituted discrimination and thus violated the Constitution's Equal Protection Clause.

In the dissenting opinion for Hopkins v. Southern California Telephone Company, Justice Holmes argued that the majority's decision was based on a misunderstanding of both the nature of property and its taxation under California law. He contended that there is no constitutional principle preventing states from taxing intangible assets differently than tangible ones, as long as it does not result in double taxation or violate due process rights. Furthermore, he disagreed with the majority's assertion that telephone lines were being taxed twice - once as real estate and again as part of a franchise - arguing instead that they were two distinct forms of property subject to separate taxes. Finally, Holmes criticized his colleagues for overstepping their judicial authority by interfering with state tax policy decisions without clear evidence of constitutional violations.