The Migratory Bird Treaty Act was a treaty between the United States and Canada. Congress passed a statute to enforce this treaty, allowing the Secretary of Agriculture to formulate regulations to enforce the Act. The State of Missouri (P) filed a bill in equity to enjoin Holland (D), the United States game warden, from enforcing the Act. P claimed that the statute unconstitutionally interfered with state rights given by the tenth amendment and that it had a pecuniary interest as owner of the wild birds which was being interfered with. In a previous treaty, Congress attempted to regulate the killing of migratory birds. A 1916 treaty between the U.S. and Great Britain provided for closed hunting seasons on certain birds and that the treaty would be codified by each country. The Act prevented the killing, capturing, or selling of any migratory birds listed in the statute except as permitted by federal regulations compatible with those terms. The United States claimed that Congress had the power to enact the statute to enforce the treaty. The District Court held that the statute was unconstitutional.