Orange Cracker Dessert

1/2 lb. Ritz crackers (crushed)
1/4 cup sugar
1/4 cup margarine, softened
1 14oz. can sweetened condensed milk
1 6oz. can frozen orange juice (thawed)
2 small cans mandarin oranges (drained)
1 8oz. Cool Whip


Mix crackers with sugar and margarine. Press into a greased 9x13 pan, saving some crumbs for the topping. Mix the remaining ingredients together with a spoon. Spoon on top of the crust and sprinkle remaining crumbs over the top. Refrigerate.