Chapter 5 explored the detail of how international treaties shaped conduct on the battlefield and in the camps. A single issue, however, does not allow us to understand how the practice of the laws of war varies with the characteristics of those issues. From the statistical analyses in Chapter 4, issues with less scope for individual violations produce better records of compliance. How does the logic of compliance vary with this scope? This chapter provides brief case studies of four issues other than prisoners of war – aerial bombing, chemical weapons, treatment of civilians, and conduct on the high seas – that vary in the scope for individual violations. Chemical weapons have the most centralized control and the least scope because individual soldiers can use chemical weapons only when their commanding authorities provide them. All soldiers in a combat zone have the power and opportunity to commit violations against civilians (except for the rare cases in which the armies fight in sparsely populated areas such as the Western Desert of Egypt and Libya). The other two issues fall between these two because individual soldiers do not have the opportunity to commit violations but lower-level officers, such as ship captains, do. Violations as a matter of state policy can and have happened on all four issues. The cases also examine the interplay of state policy and what happens on the battlefield on these issues. As with the chapter on prisoners of war, I focus on the experiences during the World Wars.

These four issues have also been the focus of other analyses in political science. Jeffrey Legro (1995) argues that military culture – the organizational practices of a military that inculcate how battles will be fought and weapons used – predicts whether states will act with restraint during wartime. He examines aerial bombing, chemical weapons, and submarine warfare during World War II in detail. As we will see, his argument corresponds to key elements of mine, but a broader view of events suggests that law shapes how these military practices arise and play out during wartime. Richard Price (1997) contends that a taboo against the use of chemical weapons has arisen from our fears of poisoning and grown over time as a way of civilizing war.