The advent of explicit interstate rivalry analysis in the past few years has raised serious questions about the wisdom of assuming that any two states have an equal probability of engaging in war. Most wars are related to protracted, ongoing conflicts between long-term adversaries and rivals. A very small number of rivalry dyads, therefore, are disproportionately responsible for a great deal of interstate conflict. Strategic rivalries, in turn, are relationships in which decision-makers have singled out other states as distinctive competitors and enemies posing some actual or potential military threat. It is not unusual for state leaders to perceive threats from states with which they do not feel particularly competitive. The Israel-Lebanon dyad is a good example. Israeli decision-makers may feel threatened by activities that originate within Lebanese space but they do not worry much about an attack from the Lebanese army. Should Israel decide to attack targets in Lebanon, there is little the Lebanese state per se can do to deter such attacks.

It is also not unknown for two states to be competitive without appearing to pose a military threat. The French–German dyad, after 1955, provides another illustration. Both states compete for leadership in the European Union, as well as elsewhere, but they no longer regard each other as threats to their respective national security. Rivalry requires the combination of competition and the perception of threat from an enemy. The US-USSR-dominated Cold War is the outstanding illustration in recent world politics.