Cranberry Mousse Pie

In a saucepan over medium heat, bring the cranberry juice to a boil. Remove from heat, add gelatin and stir until dissolved. In a mixing bowl, beat the cranberry sauce for 1 minute. Add gelatin mixture and stir until well mixed. Chill in refrigerator for 2 1/2 hours or until thickened, but not set. Remove from fridge and fold in whipped topping until mixture in thoroughly blended. Spoon into pie shell, or dessert bowls if preferred. Chill until firm.