Realists foreground the national interest as the benchmark for intelligent foreign policy. They are certainly correct in thinking that there should be some general principles in terms of which policy is formulated and against which the goals it seeks and the means used to achieve them can be evaluated. In their absence policies are more likely to be formulated from a short-term perspective, in response to inappropriate criteria like organizational concerns and special interests, and more likely to be implemented in ways that have the potential to embarrass the country.
This said, the concept of the national interest is a deeply problematic one. Many realists think they know what it is and support or criticize policies on this basis. Their judgments are arbitrary because there is no objective way of formulating the national interest. Any conception of it inevitably—and quite properly—reflects the values and goals of those proposing it. As people differ in their values and goals, at best, their conceptions of the national interest are logical expressions of their commitments and may or may not constitute realistic guidelines for policy. Given the often pronounced differences among people, there will be contrasting understandings of the national interest.