29 USCS § 101
§ 101. Issuance of restraining orders and injunctions; limitation; public policy
No court of the United States, as herein defined, shall have jurisdiction to issue any restraining order or temporary or permanent injunction in a case involving or growing out of a labor dispute, except in a strict conformity with the provisions of this Act [29 USCS §§ 101 et seq.]; nor shall any such restraining order or temporary or permanent injunction be issued contrary to the public policy declared in this Act [29 USCS §§ 101 et seq.].