Southern Pacific Railroad Company v. California was a case heard by the United States Supreme Court in 1886. The case involved a dispute between the Southern Pacific Railroad Company and the state of California over the taxation of the railroad's property. The railroad argued that the state's taxation of its property was unconstitutional, as it violated the Fourteenth Amendment's Equal Protection Clause. The Court ultimately ruled in favor of the state, finding that the taxation was not unconstitutional. The Court held that the state had the right to tax the railroad's property, as long as the taxation was applied equally to all similarly situated entities. The Court also held that the state had the right to impose different taxes on different types of property, as long as the taxes were applied equally. The Court's decision established the principle that states have the right to tax property, as long as the taxation is applied equally and does not violate the Equal Protection Clause of the Fourteenth Amendment.

In the case of Southern Pacific Railroad Company v. California, Justice Field delivered a dissenting opinion in which he argued that the state of California had no right to impose taxes on railroad companies for their property within its borders. He maintained that such taxation was unconstitutional and violated the Fourteenth Amendment's guarantee of equal protection under the law because it discriminated against interstate commerce by taxing only those businesses operating within one particular state. Furthermore, he argued that this type of taxation would lead to an unequal burden being placed upon railroads as compared to other forms of transportation, thus creating an unfair competitive advantage for certain industries over others. In conclusion, Justice Field believed that states should not be allowed to tax any form or business activity related solely with interstate commerce since doing so would violate both federal laws and constitutional protections afforded all citizens regardless of where they reside or conduct business activities.