In the case of Sears, Roebuck & Co. v. County of Los Angeles in 1980, the U.S Supreme Court ruled that California's method for assessing property taxes did not violate the Commerce Clause or Equal Protection Clause of the Constitution. The court held that a state may use different methods to assess locally owned and out-of-state-owned properties as long as it does not discriminate against interstate commerce or deny equal protection under law. In this case, Sears had argued that its stores were assessed at higher rates than similar local businesses because they were part of an interstate chain while others were independently owned and operated within California only.

In the dissenting opinion for Sears, Roebuck & Co. v. County of Los Angeles, Justice Brennan disagreed with the majority's ruling that California's method of property tax assessment did not violate the Equal Protection Clause of the Fourteenth Amendment. He argued that this system created a significant disparity in taxation among similarly situated taxpayers and thus violated principles of equal protection under law. The justice further contended that while states have wide latitude to create their own systems for taxing real property, they must still comply with constitutional requirements for fairness and equality; he believed California’s system failed to do so due to its unequal treatment of similar properties based on arbitrary factors such as date of purchase or improvements made by owners after acquisition.