Napoleon's military success stemmed not from inventing new ways of war, but from mastering the available tools and concepts of his era to a degree his opponents had not. This historical lesson serves as a warning for the modern US, whose slow adaptation to existing threats like drones suggests it is failing to master the current military landscape.

Leaders like Churchill clung to outdated strategies emphasizing speed and surprise. This Napoleonic mindset consistently failed against the realities of modern defensive technology like machine guns and barbed wire, as seen in the futile attacks at Gallipoli.

The telegraph enabled near-instant communication, tempting political leaders like President Lincoln to micromanage military campaigns from afar. However, this often failed, highlighting a timeless tension where communication technology outpaces effective command structures, creating an illusion of control that doesn't actually exist.

Historian Bruce Catton portrays General George McClellan, the "tech bro of his day," as a brilliant engineer promoted rapidly but too risk-averse to be an effective commander. His story serves as a counterargument to the modern idea that simply elevating technically skilled individuals will produce better military leaders without experiential learning.

Military technology often evolves incrementally. However, a breakthrough like the Maxim machine gun can suddenly render centuries of established doctrine—such as the drilled infantry charge—completely obsolete. This creates a strategic crisis that forces an equally radical technological and tactical response, like the tank.

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.

The majority of soldiers on the Western Front never killed an enemy in personal combat. Two-thirds of casualties were from artillery, making death an industrialized and distant phenomenon. A soldier could serve and see combat without ever laying eyes on a live opponent.

Promotion was based almost entirely on time in service, not merit. This led to absurd situations where a proven general like George Meade was technically junior to the less competent Ambrose Burnside because of their commission dates, forcing convoluted command arrangements during critical campaigns.

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.