What is the theme in The Fate of Liberty by Mark E. Neely, Jr.?

The Fate of Liberty maintains that by and large, both sides in the American Civil War live up to the standards of "civilized" or "Christian" warfare, despite a number of temptations to depart from them. At sea, Union ships obey international law that prescribes releasing seamen on neutral ships caught trying to run the blockade into Southern ports. Most ships are British, and the crews are multinational.