Though NEO writers tend to focus on formal IOs, this approach is far more
theoretical in its objectives than the earlier legal-descriptive tradition in the
field of international law. Formal rules are only one aspect of IOs according to
the NEO school and they are not the most important determinant of state
behavior: ‘From the NEO perspective, concentration on formal legal structures
may prove not only incomplete but also misleading, since the effective
enforcement of rules assumed by the formal approach is often missing,
particularly in international relations’ (Yarbrough and Yarbrough, 1990, p.
257). Informal institutions and behavioral norms play a prominent role. Much
like regime theory, then, NEO applications to IO suggest that the stark
dichotomy presented by some IR scholars between a hierarchic and ordered
domestic arena and an anarchic international order is misleading.