Putting into perspective « psychological » methods with the gist of scholarly works in political sciences, history, economy, or sociology allows the authors to draft a grid that helps understand the phenomenon of mass destruction arms proliferation, based on the leaders’ psycho-sociological dimension. It appears that a « proliferating leader » not only reacts to a given situation, but that his outlook on nuclear arms proliferation and his actions are very much influenced by several essential determinants : national resources, the country’s history and strategic context ; the type of political government ; the leader’s personal history and typology ; the country’s allies and its international dependence ; the interior power elite and mediators ; public opinions. – Summary AFRI-2002