42 U.S.C. § 2000a-5
Whenever the Attorney General has reasonable cause to believe that any person or group of persons is engaged in a pattern or practice of resistance to the full enjoyment of any of the rights secured by this subchapter, and that the pattern or practice is of such a nature and is intended to deny the full exercise of the rights herein described, the Attorney General may bring a civil action in the appropriate district court of the United States by filing with it a complaint (1) signed by him (or in his absence the Acting Attorney General), (2) setting forth facts pertaining to such pattern or practice, and (3) requesting such preventive relief, including an application for a permanent or temporary injunction, restraining order or other order against the person or persons responsible for such pattern or practice, as he deems necessary to insure the full enjoyment of the rights herein described.
In any such proceeding the Attorney General may file with the clerk of such court a request that a court of three judges be convened to hear and determine the case. Such request by the Attorney General shall be accompanied by a certificate that, in his opinion, the case is of general public importance. A copy of the certificate and request for a three-judge court shall be immediately furnished by such clerk to the chief judge of the circuit (or in his absence, the presiding circuit judge of the circuit) in which the case is pending. Upon receipt of the copy of such request it shall be the duty of the chief judge of the circuit or the presiding circuit judge, as the case may be, to designate immediately three judges in such circuit, of whom at least one shall be a circuit judge and another of whom shall be a district judge of the court in which the proceeding was instituted, to hear and determine such case, and it shall be the duty of the judges so designated to assign the case for hearing at the earliest practicable date, to participate in the hearing and determination thereof, and to cause the case to be in every way expedited. An appeal from the final judgment of such court will lie to the Supreme Court.
In the event the Attorney General fails to file such a request in any such proceeding, it shall be the duty of the chief judge of the district (or in his absence, the acting chief judge) in which the case is pending immediately to designate a judge in such district to hear and determine the case. In the event that no judge in the district is available to hear and determine the case, the chief judge of the district, or the acting chief judge, as the case may be, shall certify this fact to the chief judge of the circuit (or in his absence, the acting chief judge) who shall then designate a district or circuit judge of the circuit to hear and determine the case.
It shall be the duty of the judge designated pursuant to this section to assign the case for hearing at the earliest practicable date and to cause the case to be in every way expedited.
42 U.S.C. § 2000a-5