The transportation of persons is "commerce," within the meaning of U.S. Const. art. I, § 8. It is nevertheless true that the states are not wholly precluded from exercising their police power in matters of local concern even though they may thereby affect interstate commerce.
A resident of California brought his brother in-law from Texas to California. His brother in-law was indigent, and a complaint was filed against him under Cal. Welf. & Inst. Code § 2615, which made it illegal for a person to knowingly bring a non-resident indigent into California. The Superior Court of California convicted the resident under the statute for bringing an indigent non-resident into California after it upheld that Cal. Welf. & Inst. Code § 2615 was a valid exercise of the police power of the State of California. The case was appealed to the Supreme Court of the United States.
Was the statute valid?
On certiorari review, the United States Supreme Court held that the statute was an unconstitutional barrier to interstate commerce, as it conflicted with the Commerce Clause, U.S. Const. art. I, § 8. The Commerce Clause had been interpreted to include the transportation of persons as commerce. Additionally, indigent non-residents who entered California were deprived of the opportunity to exert political pressure upon the California legislature to obtain a change in policy. Defendant's conviction under the statute could not be sustained.