John Keegan on The War of Northern Aggression

"Railways revolutionised warmaking on land, and the American Civil War was the first to demonstrate that trend.  Indeed, it is often now represented as a purely railway war, in which the North's success in first cutting the rail connections between the populous south-east and the productive south-west at the Mississippi line, and then dividing the south-east's internal system by seizing the Chattanooga-Atlanta link in 1864, fragmenting its territory into zones that lacked economic self-sufficiency, and ensured the ultimate collapse of Southern secession, through want of supply to fighting armies, even though, ragged and hungry though they were, they could defy the Union on the battlefield to the end."

Let me pull one phrase and state it in isolation

...fragmenting its territory into zones that lacked economic self-sufficiency...

Given our current level of specialization compared to the South in 1860, I would say we are about thirty times more vulnerable to this tactic.

Yep, sure enough.  I am going to plant a garden this year.