 Sixth, at least under modern conditions, revolutionary wars have the potential to persist longer than interstate wars as they have traditionally been conducted, and hence are likely to involve more human and material destruction other things being equal, because of interventions that serve not to end them but rather to prolong them. It is a feature of contemporary revolutionary wars that they are seldom left to the primary parties. Instead, rival states or groups of rival states often support different sides. In interstate wars, the conflict typically ends when it is clear that there is an indefinitely persisting stalemate and hence both sides are compelled to seek a negotiated peace or when one side overwhelms the other (Wittman 1979; Jones, Bremer &amp; Singer 1996; Wagner 2000). But when revolutions become proxy wars between rival powers, one state is likely to intervene to resupply or otherwise support its proxy to break a stalemate or prevent the other side from achieving victor. That is why most empirical theorists of intrastate war predict that there is no end in sight to the conflict in Syria (Jenkins 2014). This problem is exacerbated by the fact that one or both of the sponsors of the conflicting sides may not have as its top strategic aim a victory for its side. Instead, the dominant goal may actually be to prolong the conflict. To the extent that revolutionaries or regimes who oppose them ought to take the traditional jus ad bellum requirement of likelihood of success into account and also ought to heed the requirement of proportionality, their task is complicated by strategic dynamic that occurs when revolutions are not simple two party affairs, but proxy contests between other parties as well. Intervention makes calculations of both likelihood of success and proportionality more problematic. And if there is a presumption against war unless likelihood of success and proportionality are relatively certain, then it follows that the justification for revolutionary war is even more problematic, other things being equal, than for interstate war.