Simmerman v. Nebraska was a United States Supreme Court case that dealt with the issue of whether a state could impose a tax on a non-resident's income from real estate located in the state. The case was brought by a Nebraska resident, John Simmerman, who owned real estate in the state of Nebraska but lived in the state of Iowa. Simmerman argued that the state of Nebraska had no right to impose a tax on his income from the real estate, as he was not a resident of the state. The Supreme Court ruled in favor of Simmerman, holding that the state of Nebraska could not impose a tax on the income of a non-resident from real estate located in the state. The Court reasoned that the power to tax is an attribute of sovereignty, and that the state of Nebraska had no authority to impose a tax on a non-resident's income from real estate located in the state. The Court further held that the power to tax is limited to the state in which the property is located, and that the state of Nebraska had no authority to impose a tax on a non-resident's income from real estate located in the state. The Court's decision in Simmerman v. Nebraska established the principle that a state cannot impose a tax on a non-resident's income from real estate located in the state. This principle has been applied in numerous cases since then, and has been used to protect the rights of non-residents to receive income from real estate located in a state without being subject to taxation by that state.

Justice Field delivered the dissenting opinion in Simmerman v. Nebraska, arguing that the state of Nebraska had violated the Fourteenth Amendment by denying a citizen his right to vote based on race or color. He argued that this was an unconstitutional act and should be overturned as it deprived citizens of their rights without due process of law. He further noted that while states have broad powers to regulate elections, they cannot deny people their constitutional rights without cause or justification. Justice Field concluded by stating that if such practices were allowed to continue unchecked then it would lead to "the most odious discrimination against classes and individuals."