The Empresa Siderurgica, S. A., et al. v. County of Merced et al., 1948 case involved a dispute over the taxation of property owned by foreign corporations in California. The plaintiffs, Empresa Siderurgica and other foreign corporations, argued that they were being unfairly taxed on their properties because the county was not considering depreciation when assessing the value of their assets for tax purposes. They claimed this violated both state law and the Equal Protection Clause of the Fourteenth Amendment to U.S Constitution as domestic companies' properties were assessed at lower values due to consideration of depreciation. However, The Supreme Court ruled against them stating that there was no violation since all personal property within California - whether owned by residents or non-residents - is subject to tax assessment without regard for its physical condition or depreciation status under existing laws during that time period (Revenue & Taxation Code Section 405). Therefore, it concluded that there was no discrimination against these foreign corporations.

In the dissenting opinion for Empresa Siderurgica, S. A., et al. v. County of Merced et al., Justice Frankfurter argued that the majority's decision to uphold California's tax on foreign corporations was inconsistent with previous rulings and violated principles of international comity. He contended that a state should not be allowed to impose taxes on property located outside its jurisdiction, especially when it is owned by a foreign corporation and used exclusively in foreign commerce. The justice believed this would lead to double taxation and could potentially harm U.S.'s relations with other countries if they decided to retaliate by imposing similar taxes on American companies operating abroad.