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The national interest, often referred to by the French expression raison d'État (English: "reason of State"), is a country's goals and ambitions, whether economic, military, cultural or otherwise. The concept is an important one in international relations, where pursuit of the national interest is the foundation of the realist school.
In early human history the national interest was usually viewed as secondary to that of religion or morality. To engage in a war rulers needed to justify the action in these contexts. The first thinker to advocate for the primacy of the national interest is usually considered to be Niccolò Machiavelli.
The practice is seen as being employed by France under the direction of its Chief Minister Cardinal Richelieu in the Thirty Years' War when it intervened on the Protestant side, despite its own Catholicism, to block the increasing power of the Catholic Holy Roman Emperor. At Richelieu's prompting, Jean de Silhon defended the concept of reason of state as "a mean between what conscience permits and affairs require." The notion of the national interest soon came to dominate European politics that became fiercely competitive over the next centuries. It is a form of reason "born of the calculation and the ruse of men" and makes of the state "a knowing machine, a work of reason"; the state ceases to be derived from the divine order and is henceforth subject to its own particular necessities.[page needed]
States could now openly embark on wars purely out of self-interest. Mercantilism can be seen as the economic justification of the aggressive pursuit of the national interest.
A foreign policy geared towards pursuing the national interest is the foundation of the realist school of international relations. The realist school reached its greatest heights at the Congress of Vienna with the practice of the balance of powers, which amounted to balancing the national interest of several great and lesser powers.
Metternich was celebrated as the principal artist and theoretician of this balancing but he was simply doing a more or less clean copy of what his predecessor Kaunitz had already done by reversing so many of the traditional Habsburg alliances and building international relations anew on the basis of national interest instead of religion or tradition.
These notions became much criticized after the bloody debacle of the First World War, and some sought to replace the concept of the balance of power with the idea of collective security, whereby all members of the League of Nations would "consider an attack upon one as an attack upon all," thus deterring the use of violence for ever more. The League of Nations did not work, partially because the United States refused to join and partially because, in practice, nations did not always find it "in the national interest" to deter each other from the use of force.
The events of World War II along with World War I, led to a rebirth of Realist and then Neo-realist thought, as international relations theorists re-emphasized the role of power in global governance. Many international relations theorists blamed the weakness of the League of Nations for its idealism (contrasted with realism) and ineffectiveness at preventing war, even as they blamed mercantilist beggar thy neighbor policies for the creation of fascist states in Germany and Italy. With hegemonic stability theory, the concept of the US national interest was expanded to include the maintenance of open sea lanes and the maintenance and expansion of free trade.
Today, the concept of "the national interest" is often associated with political realists who fail to differentiate their policies from "idealistic" policies to seek to inject morality into foreign policy or promote solutions that rely on multilateral institutions which might weaken the independence of the state.
As considerable disagreement exists in every country over what is or is not in "the national interest," the term is as often invoked to justify isolationist and pacifistic policies as to justify interventionist or warlike policies. It has been posited that the term is a euphemism used by powerful countries for geopolitical aims such as nonrenewable natural resources for energy independency, territorial expansionism and precious metals in smaller countries. In that case, euphemism usage is necessary to stifle voices opposed to an interventionistic or warhawk foreign policy.