Leary v. Long was a United States Supreme Court case that dealt with the issue of whether a state could impose a tax on the income of a non-resident. The case was brought by a resident of New York, who had been assessed a tax on his income from a business in Massachusetts. The plaintiff argued that the tax was unconstitutional, as it violated the Due Process Clause of the Fourteenth Amendment. The Supreme Court held that the tax was constitutional, as it was a valid exercise of the state's power to tax. The Court noted that the tax was not discriminatory, as it applied equally to all non-residents, regardless of their state of residence. Furthermore, the Court held that the tax was not an undue burden on interstate commerce, as it was not excessive or oppressive. In conclusion, the Supreme Court held that the tax was constitutional, as it was a valid exercise of the state's power to tax. The Court noted that the tax was not discriminatory, and did not impose an undue burden on interstate commerce.

In Leary v. Long, the United States Supreme Court was asked to decide whether a state statute that prohibited the sale of intoxicating liquors within four miles of any schoolhouse violated the Fourteenth Amendment's Equal Protection Clause. The majority opinion held that it did not violate equal protection because there was no discrimination against any particular class or group in its application and thus upheld the law. Justice Field dissented from this decision, arguing that while states have broad authority to regulate liquor sales for public health and safety reasons, they cannot do so in an arbitrary manner which discriminates against certain classes or groups without providing some rational basis for their action. He argued further that since there is no evidence presented as to why such a prohibition should be limited only to schools located within four miles of them, it appears on its face to be an unreasonable restriction which violates equal protection principles by discriminating between those who live near schools and those who do not.