In 1933, he left Yale to become the Assistant Solicitor at the Department of the Interior under Harold L. Ickes. During his first tour at Interior, he authored the Code of Fair Competition for the Petroleum Industry (1933), and the Connally Hot Oil Act of 1935 in the wake of the Supreme Court's decision to strike down the National Industrial Recovery Act (NIRA). Specifically, it revived the portion of the original legislation that regulated the flow of oil between states. Ostensibly enacted to protect the industry from "contraband oil" in order to stabilize falling prices.