In this article, Adam Watson’s use of ideal-types is revisited in order to distinguish between various kinds of international orders over time, and address the different types of war which are logically possible in relation to them. The argument is that war differs between ordered and disordered circumstances, as well as among members, or between members and non-members of a given order. The aim is, first, to analytically distinguish between various types of phenomenon which all happen to include organised violence between political entities, and all be called war; and second, to demonstrate the utility of abstracting far enough from actual history to be able to apply analytical categories, a purpose which Watson would recognise. This contributes to freeing theorising about war from its Westphalian and Eurocentric straightjacket.