"Why Wars Widen offers a theoretical explanation for war widening based on the decisiveness of warfare in a given era. It argues that conflicts are most likely to spread when the effects of warfare are limited, as states seek limited gains with low cost. In an era when warfare is decisive, in other words, an era of total war, wars are less likely to widen.

Great Powers will only enter such a conflict to redress the balance of power. War widening is less likely in such cases, although it is often explosive when it occurs. By understanding whether a war occurs in an era of total war or limited war, we can then assess how likely that conflict is to spread."--Jacket.