Self-defense leads a double life, primary rule in the morning and secondary rule in the evening, as suggested by the Commission in its commentary adopted in 2001. If the quality of "law" (and primary rule) of self-defense has long been disputed, its quality of "circumstance", "situation", of "common condition" never was denied as such. This seems paradoxical. If, indeed, the quality of "primary rule" of self-defense seems indisputable, quality of "circumstances preclude wrongfulness", as provided in Article 21 of the Code on the responsibility of States is much more controversial and problematic. Certainly, at first glance, Article 21 might seem logical and interesting. This chapter discusses that the rule introduced by Article 21 is of little use in regard to the first hypothesis because the liability law already provides answers in this area, when it could, perhaps, have utility with respect to the second situation.