Within the debate on international relations an increasing amount of scholars have acknowledged that the debate is unnecessarily entrenched in old paradigms and that the dividing lines are in many cases arbitrary. This theory-developing paper is an answer to the call for cross-fertilization specifically between realism and constructivism. Here the concept of national interests, and its role in the realist tradition of international relations, is re-examined. The argument is made that, classical- and neo-classical-, realist theories should take identity into account when explaining states pursuit of national interests. This is done not only by identifying and explaining the constructivist theories that is useful to realism but also by illuminating an, so far, unexplored potential within realism to directly include identity into its theories. In the final part of the paper the usefulness of the augmented concept of national interests is also illustrated by using the concept to explain Sweden's reluctance against a NATO-membership.