Hubris
One of the overriding themes that pervades the book is the hubris of those involved. Keeping in mind that the central events of the book take place just three short years after the sinking of the Titanic, inexplicably those associated with building and maintaining the Lusitania remained convinced it was not vulnerable to being sunk by any know weapons of war. Further undermining this willed ignorance was the hubris of British leaders toward the potential for a very recently developed new kind of weapon to present any serious threat to either a ship as large as the Lusitania or a power as great as Britain.
The Rise of the Submarine
Swimming beneath the theme of hubris, but in constant concert with it, is the theme of how the newest weapon of war would change everything. Submarines used as naval vessels in wartime traces at least as far back as the American Civil War, some half-century earlier. The Monitor and the Merrimack enjoyed very limited impact on the course of that war and as such the idea of a submarine was always greater than the actual reality. As such, few in England saw the German U-Boats as any kind of serious threat. Notably, the author Sir Author Conan Doyle was one of those who saw the future very clearly. So did the Germans. And so the lack of foresight and understanding on the part of those charged with protecting the great and glorious British Empire contributed to the overall sense of hubris that allowed circumstances to develop which inexorably led to the sinking of the ship.
American Neutrality
For most of World War I, Americans had been more than content to let European soldiers fight their own war on their own battlefields. Nothing indicated that the Germanys were really seriously likely to expand that battlefield across the Atlantic Ocean when they having trouble enough just defeating their European neighbors. Still, as the war dragged, it was becoming increasingly apparent to both sides that if America were to reject their officially neutral stance and officially enter the conflict with troops, those troops would inevitably be fighting on the side of the British and the French. The issue of American neutrality is essential to the narrative because still not-completely-answered questions about what exactly happened to the Lusitania: were the German alone responsible for sinking it with a torpedo or there was a more complex conspiracy in which the ship and its passengers could be sacrificed for the larger gain of using the attack to provoke America into entering the war and thus hastening what seemed an inevitable defeat of the Germans, but with no clear timeline in place for that victory to be accomplished on their own.
