52 U.S.C. § 10504

Whenever the Attorney General has reason to believe that a State or political subdivision (a) has enacted or is seeking to administer any test or device as a prerequisite to voting in violation of the prohibition contained in section 10501 of this title, or (b) undertakes to deny the right to vote in any election in violation of section 10502 or 10503 of this title, he may institute for the United States, or in the name of the United States, an action in a district court of the United States, in accordance with sections 1391 through 1393 11 See References in Text note below. of title 28, for a restraining order, a preliminary or permanent injunction, or such other order as he deems appropriate. An action under this subsection shall be heard and determined by a court of three judges in accordance with the provisions of section 2284 of title 28 and any appeal shall be to the Supreme Court.