Homer v. The Collector is a United States Supreme Court case that dealt with the issue of taxation on imports. Homer, an importer of goods from abroad, argued that he should not be subject to taxes imposed by Congress as it was unconstitutional for them to do so without apportioning the tax among all states according to their population. The Collector argued that since this was a revenue-raising measure and not one intended for regulation or protectionism, it did not need to be apportioned in such a way. Ultimately, the court sided with the Collector and held that Congress had authority under its taxing power to impose duties on imported goods regardless of whether they were apportioned among all states or not. This decision established precedent which has been used ever since when determining if federal laws are constitutional based upon how they affect interstate commerce and taxation powers granted by Congress under Article I Section 8 Clause 1 of the Constitution (the Commerce Clause).

In Homer v. The Collector, the Supreme Court was asked to decide whether a tax imposed by Congress on income derived from United States bonds and other securities violated the Constitution. Justice Field wrote a dissenting opinion in which he argued that the tax was unconstitutional because it interfered with contracts between private parties and constituted an illegal taking of property without due process of law. He further argued that since Congress had no power to impose taxes on such income, any attempt to do so would be invalid under both state and federal constitutions. Finally, he noted that even if there were some constitutional authority for imposing such a tax, this particular one did not meet all necessary requirements as it applied only to certain classes of persons or corporations rather than being uniform throughout the country as required by Article I Section 8 Clause 1 of the U.S Constitution.