Bonnifield v. Price was a United States Supreme Court case that dealt with the issue of whether a state could tax the income of a non-resident. The case was brought by a resident of the state of Virginia, who was being taxed on income he had earned in the state of West Virginia. The plaintiff argued that the taxation of his income was unconstitutional, as it violated the Due Process Clause of the Fourteenth Amendment. The Supreme Court ultimately ruled in favor of the plaintiff, finding that the taxation of his income was unconstitutional. The Court reasoned that the taxation of a non-resident's income was a violation of the Due Process Clause, as it was an unreasonable burden on the non-resident. The Court further held that the taxation of a non-resident's income was a violation of the Privileges and Immunities Clause of the Fourteenth Amendment, as it denied the non-resident the same privileges and immunities as a resident of the taxing state. In conclusion, the Supreme Court held that the taxation of a non-resident's income was unconstitutional, as it violated both the Due Process Clause and the Privileges and Immunities Clause of the Fourteenth Amendment. This ruling established an important precedent, as it established that states cannot tax the income of non-residents.

Justice Harlan delivered the dissenting opinion in Bonnifield v. Price, arguing that the majority's decision was contrary to established precedent and would lead to a dangerous expansion of federal power. He argued that Congress had no authority under Article I of the Constitution to pass legislation regulating labor disputes between private parties, as it did with this case. The majority held that Congress could regulate such matters if they affected interstate commerce; however, Justice Harlan argued that this interpretation was too broad and would allow for an unprecedented level of federal control over state affairs. Furthermore, he noted that there were other remedies available at law which should be used instead of allowing Congress to intervene in these types of cases. In conclusion, Justice Harlan believed the Court should have followed existing precedent rather than expanding congressional powers beyond what is authorized by Article I or any other part of the Constitution.