President Clinton today demanded immediate congressional action on his anti-terrorism package, despite GOP warnings that a controversial FBI promotion could stall it. "It needs to pass and pass now," Clinton said. "Nothing can justify turning this bill into a political football." He was referring to a suggestion made Sunday by House Speaker Newt Gingrich that Attorney General Janet Reno's nomination of Larry Potts as FBI deputy director "will further slow down the terrorist legislation and will mean even greater concern over civil liberties, which I don't think is inappropriate." Potts oversaw the 1993 siege at theBranch Davidian compound in Waco, Tx., and the disastrous 1992 shootout at the home of white separatist Randall Weaver in Idaho, for which he was censured last month. Gingrich said those incidents, which have become rallying cries amonganti-government paramilitaries, aggravate a "genuine fear" of the federal government among rural western Americans.