If in any proceeding instituted by the Attorney General or an aggrieved person under any statute to enforce the voting guarantees of the fourteenth or fifteenth amendment in any State or political subdivision the court finds that violations of the fourteenth or fifteenth amendment justifying equitable relief have occurred within the territory of such State or political subdivision, the court, in addition to such relief as it may grant, shall retain jurisdiction for such period as it may deem appropriate and during such period no voting qualification or prerequisite to voting or standard, practice, or procedure with respect to voting different from that in force or effect at the time the proceeding was commenced shall be enforced unless and until the court finds that such qualification, prerequisite, standard, practice, or procedure does not have the purpose and will not have the effect of denying or abridging the right to vote on account of race or color, or in contravention of the voting guarantees set forth in section
1973b
(f)(2) of this title: Provided, That such qualification, prerequisite, standard, practice, or procedure may be enforced if the qualification, prerequisite, standard, practice, or procedure has been submitted by the chief legal officer or other appropriate official of such State or subdivision to the Attorney General and the Attorney General has not interposed an objection within sixty days after such submission, except that neither the court’s finding nor the Attorney General’s failure to object shall bar a subsequent action to enjoin enforcement of such qualification, prerequisite, standard, practice, or procedure.