The act of concluding the treaty is then done successively for Kant, on two occasions: first, as a treaty between allies, sovereign power and the principles according to which it can be exercised legally, and second, as a treaty between states that introduce an analogous work of principles and an analogous sovereign authority, this time in the form of a “federation of free states”.  For Rawls, as for most contemporary theorists of the treaty, the purpose of the agreement is not, at least directly, the reasons for political engagement, but the principles of justice that govern the fundamental institutions of society. . . .