In People v. Commissioners of Taxes and Assessments, the Supreme Court of the United States was asked to decide whether a state could tax the income of a non-resident. The case involved a New York statute that imposed a tax on the income of non-residents who received income from real estate located in the state. The plaintiff, a non-resident, argued that the statute was unconstitutional because it violated the Due Process Clause of the Fourteenth Amendment. The Supreme Court held that the statute was constitutional. The Court reasoned that the Due Process Clause did not prohibit a state from taxing the income of a non-resident if the income was derived from property located within the state. The Court noted that the state had a legitimate interest in taxing the income of non-residents who received income from property located within the state. The Court also noted that the tax was not so onerous as to be oppressive or confiscatory. In conclusion, the Supreme Court held that the New York statute was constitutional and that the state could tax the income of non-residents who received income from real estate located in the state.

In People v. Commissioners of Taxes and Assessments, the Supreme Court was asked to determine whether a state statute that allowed for taxation on real estate owned by non-residents violated the Constitution's Contract Clause. Justice Field delivered a dissenting opinion in which he argued that while it is true that states have broad authority to tax property within their borders, this power must be exercised with caution when it comes to contracts already made between parties. In this case, the contract had been entered into prior to any enactment of such taxes and thus should not be subject to them retroactively; doing so would violate both the spirit and letter of the Contract Clause as well as principles of fairness. He concluded by stating his belief that if Congress had intended for such taxes on existing contracts then they would have included language explicitly allowing for them in legislation rather than leaving it up to individual states' discretion.