How can the various religions of the world enter into a fruitful dialogue in moral matters? Can they hope to come to an agreement on a clear and significant common ethic, without having to disown any essential tenets of their own doctrine? Aristotelian philosophy and specifically the light it throws on the connatural links which bind together religions, morals and politics, may help us answer questions as these. After having shown that any authentic moral experience (either explicitly or implicitly) contains an experience of God, the author draws an inventory of the moral deposit common to all religions, and he notes that the meaning of many of their moral positions depends on the (either explicit or implicit) acknowledgment for personal Creator-God. He then tackles a specially thorny subject which raises difficulties both in the dialogue between the religions themselves and between the religions and the State: the problem of the legalization of abortion. Arguments taken from political ethics tend to show that legalizing abortion undermines the very foundation both of the bat de droit and of democracy. In his conclusion, the author stresses the necessity and sketches the conditions of a truly inter-religious dialogue.