Vers une diplomatie des peuples ? L’opinion publique et les crises franco-anglaises des années 1840

International audience ; A first media system gets organized from the 1930's, in the Western Europe, around the written press. The foreign policy has an essential place in it, allowing the public opinion to seize international affairs. This new actor of the international relations claims the advertising of the foreign policy and establish itself as a judgment authority; indeed, it considers itself the main moral resource of the country and its power's founding principle. This opinion makes it heard to claim a moral foreign policy, in front of a liberal state whose main interests are its own. This demand of a good and universal policy promotes the emergence of an international public opinion, sharing values. This initiation stays in the tight European public space. The aim of this article is to show that, against the decision-maker's feeling, the assertion of the public opinion in international affairs has mainly generated peace effects. The best mutual knowledge has allowed taming the opposite media culture. Fighting for peace between civilized nations of equal dignity, against the State warmongering, the French and English public opinion have participated to the invention of the mediation concept : as a matter of fact, the informal tribunal of the opinion prefigured the judiciarization of the international society. The public opinion has also claimed a democratization of each state, and of their relations, for peace. In this way, the call to a diplomacy of the peoples, affiliated to the peace project inherited from Kant, has been exceeding the notion of an opinion proclaiming the refusal of the people to be opposed between them, consubstantial place to the refusal to be private, for all of them, of the command of the foreign policy questions. ; Un premier système médiatique s'organise à partir des années 1830, en Europe occidentale, autour de la presse écrite. La politique étrangère y tient une place primordiale. L'opinion, nouvelle actrice des relations internationales, revendique la publicité de la diplomatie ...