“Free will” – that beautiful matrix of classic liberal private law (they say “Whoever contracts accepts that it’s fair”) is in reality an important instrument for regulating social relationships. The observation of the real – effective – functioning of this legal tool reveals in a paradigmatic way the identity of the individual in post-modern society whose freedom is both immense and insignificant, and an unlimited source of power and servile subjection to directives of public and private organizations which effectively establish what should be desired. Exercising that prerogative means adhering to norms that are imposed by oneself –in fact- independently of its source, more than in a measure that can be determined. The above is applied to question the principle of legality in state contracts in which the real principle of “free will” acts as an effective warranty against state abuse.