Hello and welcome back. This is WAR 1870–1949: How Empires Rise and Fall. We’re keeping the format, keeping the big machine in view, but we’re going to keep pressing the ear to the envelope—because the ugly truth isn’t in the treaty language, it’s in what a person can barely bring themselves to write.

Picture the mail bag moving in the opposite direction of the front. It is the strangest artery of the war: paper carrying love and reassurance and small domestic facts through a world where flesh is being torn apart. A soldier writes because writing is the last thing that still feels human. A mother reads because reading is the only way she can pretend the war is not eating her family. The empire encourages the mail because it stabilizes morale—because a man who feels connected to home can endure longer. Even intimacy becomes a resource in war ...