WASHINGTON - No Republican senator has said publicly he will challenge Mississippi's Trent Lott for majority leader. Attention, however, is focusing on four lawmakers should GOP senators decide to oust Lott when they meet Jan. 6: Don Nickles, 54, of Oklahoma, won a seat in the Senate in 1980 at age 31. For the past six years, he has served as GOP whip, second in power to the party leader. He is set to take over as Budget Committee chairman in the next Congress, where his pro-business, pro-defense views would shape future budgets. He has suggested that savings could be...