The concept of the national interest is used in both political analysis and political action. As an analytic tool, it is employed to describe, explain, or evaluate the sources or the adequacy of a nation’s foreign policy. As an instrument of political action, it serves as a means of justifying, denouncing, or proposing policies. Both usages, in other words, refer to what is best for a national society. They also share a tendency to confine the intended meaning to what is best for a nation in foreign affairs.