The constitution of the new international system was the Final Act of the Congress of Vienna, supplemented in time by various “amendments” ratified at subsequent congresses. The Congress was therefore the constitutional convention of Europe, and it was seen as such by the state-nations that brought it into being. This constitution represents a response to three points of acute sensitivity to the state-nation: the self-consciousness of the new constitutional form, which could not depend merely upon custom for its legitimacy and must therefore earn its right to govern through the studied design and implementation of its institutions; the role of public opinion, which had become so influential in this new order that it demanded recognition by politicians; and the requirement that government policy be justifiable on the basis of articulated principles that themselves were taken as legitimate (thus requiring that the judgment of legitimacy go well beyond merely assessing the head of state). With regard to international affairs, these three points of importance played out in the following way, respectively: there was a demand for a particular legal instrument, consciously designed to prevent future wars in Europe; when public opinion became engaged by matters abroad, there had to be a way for politicians to replace diplomats as the effective actors; and inherited principles regarding the “general interest” of all states, and of the “balance of power”—set forth in earlier international constitutions and enjoying the prestige and legitimacy of tradition—had to achieve a new consensus among the powers in order for the behavior of these states to seem principled yet these principles had to be updated and modified in order for them to be practical.