Mix 1 1/2 cups graham cracker crumbs with 6 tbsp melted butter and 1/4 cup granulated sugar in a bowl. Press this mixture firmly into the bottom of a 9-inch springform pan. Chill while you make the filling—this prevents the crust from getting soggy later.
Beat 16 oz softened cream cheese and 1/2 cup powdered sugar together until completely smooth, about 2 minutes. Don't skip this step or you'll end up with lumps (trust me, I learned that the hard way).
Gently fold the whipped topping into the cream cheese mixture using a rubber spatula. Keep folding until no white streaks remain, but don't overmix or you'll deflate all that fluffiness.
Spread exactly half the creamy filling over your chilled crust in an even layer. This becomes your first patriotic layer for this no bake cheesecake masterpiece.
Toss 1 cup diced strawberries with 1 tbsp lemon juice in a small bowl, then arrange them on top of the first filling layer. They'll release just enough juice to flavor the layer below without making everything watery.
Add the remaining filling on top of the strawberry layer, smoothing it into an even surface. Now comes the fun part—sprinkle 1/2 cup blueberries across the top in whatever patriotic pattern you want.
Refrigerate for at least 4 hours before slicing (overnight is even better). The patriotic no bake cheesecake needs this time to set up properly so you get clean, beautiful slices instead of a crumbly mess.