The State of Missouri brought a suit to prevent a game warden of the United States from attempting to enforce the Migratory Bird Treaty Act 0f 1918 and the regulations made by the Secretary of Agriculture in pursuance of the same. Missouri alleged that the statute is unconstitutional interference with the rights reserved to the States and that the acts of the defendant done and threatened under that authority invade the sovereign right of the State and contravene its will manifested in statutes.
Acts of Congress are the supreme law of the land only when made in pursuance of the Constitution, while treaties are declared to be so when made under the authority of the United States.
On 1916, a treaty between the United States and Great Britain was proclaimed by the President. It recited that many species of birds in their annual migrations traversed certain parts of the United States and of Canada, that they were of great value as a source of food and in destroying insects injurious to vegetation, but were in danger of extermination through lack of adequate protection. The treaty thus provided for specified close seasons and protection in other forms, and agreed that the two powers would take or propose their law-making bodies the necessary measures for carrying the treaty out. The Act sought to prohibit the killing, capturing, or selling any of the migratory birds included in the terms of the treaty except as permitted by regulations compatible with those terms.
Can Congress enact a law that requires States to prevent a game warden of migratory birds?
Yes, here a national interest of nearly the first magnitude is involved. It can be protected only by national action in concert with that of another nation. The subject-matter is only transitorily within the State and has no permanent habitat therein. But for the treaty and the statute there soon might be no birds for any powers to deal with. Nothing in the Constitution compels the Government to sit by while a food supply is cut off and the protectors of our forests and crops are destroyed. It is not sufficient to rely on the States. The reliance is vain. Thus, the statute and treaty must be upheld.
It is true that as between a State and its inhabitants, the State may regulate the killing and sale of such birds, but it does not follow that its authority is exclusive of paramount powers. Wild birds are not in the possession of anyone and possession is beginning of ownership. The entire foundation of the State’s rights is the presence within their jurisdiction of birds that yesterday has not arrived, tomorrow may be in another State. If we are to be accurate, we cannot put the case of the State upon higher ground than that the treaty deals with creatures that for the moment are within the state borders, that it must be carried out by officers of the United States within the same territory, and that but for the treaty the State would be free to regulate this subject itself.