War has always been an option in international affairs; few rulers before just war theory was developed felt constrained by the absence of such a moral framework. What the just war criterion provide for is a regulatory framework whereby war cannot break out before at least one side satisfies the criterion. As such, this ensures a temporal space for diplomatic negotiations to play out and if necessary, for either top-down pressure from more powerful states or bottom-up pressure from the public to alleviate any desire for war.