In the games used to study legal standardization, legal unification is never the outcome of the usual cooperative solution. Given the importance of legal unificationin practice, this property appears as a paradox. To solve this paradox, we resortto alternative notions of cooperation. We show that introducing other-regarding preferences or Kantian rules of behavior does not resolve the paradox except ina very peculiar case. By contrast, we show that legal uniformity prevails at any Berge equilibrium of our legal standardization game. This, we argue, is a first step towards a solution to the paradox of legal unification.