After mandatory administrative preliminaries, on April 4, 1952, the Union gave notice of a nationwide strike to begin April 9. The indispensability of steel as a component of substantially all weapons and other war materials for the Korean War led the President to believe that the proposed work stoppage would immediately jeopardize national defense and that governmental seizure of the steel mills was necessary in order to assure the continued availability of steel. The President, a few hours before the strike was to begin, issued Executive Order 10340. The order directed the Secretary of Commerce to take possession of most of the steel mills and keep them running. The Secretary immediately issued his own possessory orders, calling upon the presidents of the various seized companies to serve as operating managers for the United States. They were directed to carry on their activities in accordance with regulations and directions of the Secretary. The next morning the President sent a message to Congress reporting his action. Twelve days later, he sent a second message. Congress has taken no action. Obeying the Secretary's orders under protest, the companies brought proceedings in the District Court. Their complaints charged that the seizure was not authorized by an act of Congress or by any constitutional provisions. The District Court was asked to declare the orders of the President and the Secretary invalid and to issue preliminary and permanent injunctions restraining their enforcement. The District Court issued a preliminary injunction restraining the Secretary. On the same day, the Court of Appeals stayed the District Court's injunction deeming it best that the issues raised be promptly decided by the Supreme Court.