When Jose Padilla was charged in a South Florida terror-cell indictment in November, U.S. authorities boasted their case was rock solid. But in a stunning decision, a federal judge in Miami has lopped a big chunk off of the indictment, saying the government wrongly overcharged the notorious former ''enemy combatant'' and two other Muslim men. In a written order released Monday, U.S. District Judge Marcia Cooke threw out the first count of the indictment -- that Padilla and the others ''conspired to murder, kidnap and maim persons in a foreign country . . . to advance violent jihad'' abroad -- saying it repeated charges from two other counts. The ruling also could wipe out possible life sentences if Padilla, Adham Amin Hassoun and Kifah Wael Jayyousi are convicted at trial, scheduled for late January.