Brief note on the decline of interstate war

From S. Walt's post of yesterday:

I agree with [Steven] Pinker's claim that the overall level of human violence has declined significantly over the past several centuries ..., but I remain agnostic about the larger claims for a long-term reduction in inter-state violence. That trend is driven almost entirely by the absence of great-power war since 1945, and the absence of great-power war may have multiple and overlapping causes ... whose persistence is hard to forecast.

There are no interstate wars going on in the world at the moment, as far as I'm aware. (The war in Afghanistan, for example, is not an interstate war; it's an internationalized civil war. The war in Syria is a civil war, period.) Since there are roughly 200 sovereign states in the world and since there could be numerous interstate wars not involving the great powers, and yet in fact there are no interstate wars at all, it seems bizarre -- actually, it seems flat-out wrong -- to say, as Walt does, that the decline in interstate war "is driven almost entirely by the absence of great-power war...." We're dealing with a phenomenon -- the absence of interstate war -- of which the absence of great-power war is a (very important) manifestation, or sub-phenomenon if you prefer. Even if no great powers were fighting each other, a lot of other states could be fighting each other. But they're not. Walt evidently sees this as insignificant or at least as not worthy of separate mention. Why? Good question. Better go ask him directly.