Abstract

Drawing on my qualitative and quantitative research I show that the motives for war have changed in the course of the last four centuries, and that the causes of war and the responses of others to the use of force are shaped by society. Leaders who start wars rarely behave with the substantive and instrumental rationality assumed by realist and rationalist approaches. For this reason, historically they lose more than half wars than they start. After 1945, the frequency of failure rises to over 80 percent. Rationalists allow for miscalculation but attribute it to lack of information. In most wars, information was available beforehand that indicated, or certainly suggested, that the venture would not succeed militarily or fail to achieve its political goals. The war in Ukraine is a case in point.