Despite new technologies, the Civil War's generalship resembled the Napoleonic era more than WWI. Command was dominated by individual personalities and singular decisions, like Pickett's Charge, rather than the vast, impersonal, and bureaucratized military machines that would define 20th-century warfare.

Unlike wars where a nation is attacked first (e.g., Pearl Harbor), "wars of choice" lack the sustained public support needed for a long conflict. The aggressor has a political weak point, which adversaries exploit to win a war of attrition, not battlefield victories.

The proclamation was not just a moral act but a calculated strategy. By making the war explicitly about ending slavery, Lincoln made it politically impossible for abolitionist nations like Great Britain to support the Confederacy, cutting off their resources.

The infamous Supreme Court decision, which denied Black people citizenship, was more than a legal precedent; it was a political accelerant. The ruling galvanized Northern anger against slavery's expansion, directly fueling the rise of the new Republican party and Abraham Lincoln, setting the stage for the Civil War.

The "Prize Cases" reveal the legality of Lincoln's naval blockade of the South was a precarious constitutional question. Because blockades are an act of war between nations, his authority was challenged. A 5-4 Supreme Court decision validated his actions, retroactively saving the entire Union war effort from being declared unconstitutional.

While ideology played a role, a significant motivation for many Union soldiers was economic. A severe economic downturn in the late 1850s meant that for many, enlisting provided a steady salary and food, challenging the purely patriotic narrative of why men joined the army.

Generals had an outsized influence on their armies' institutional character. For example, George McClellan created a cautious, politically fraught culture in the Army of the Potomac, while Robert E. Lee instilled an aggressive ethos in the Army of Northern Virginia, shaping how they fought.

Confederate General Robert E. Lee understood he couldn't win a war of attrition. His strategy centered on high-risk plays, like invading the North, to inflict shocking defeats that would persuade the Northern public the war was unwinnable, thereby electing an administration willing to negotiate peace.

The Union's war effort succeeded via a decentralized model that leveraged private corporations for railroads and civil society groups like the U.S. Sanitary Commission for medical care. This contrasted with the Confederacy's more centralized, state-controlled approach, which ultimately couldn't match the North's capacity.