A federal court here yesterday delayed action on cable industry challenges to the new cable reregulation law until after the Clinton administration assumes office.By doing so, a three-judge U.S. District Court panel held open the possibility that the new Justice Dept. under Clinton will defend the constitutionality of the must-carry/retransmission consent provision of the cable law. The Bush administration’s Justice Dept. has announced that it will not defend must-carry, the requirement that forbids cable operators from dropping broadcast signals. Retransmission consent refers to the portion of the law allowing broadcasters to charge cablers for carriage of local signals. The court also issued a “standstill order” in which parties in the cable rereg suits agreed that there will be a four-month delay in Federal Communications Commission enforcement against cable operators accused of not allowing public broadcasters access to a cable system via must-carry.