Tactically the Union Army was defeated in every major battle and engagement in the brutal Wilderness campaign.
C: disease would kill ideas before they even spread
The answer is Simon Bolivar
In the United States, there was a domino effect boom - we were primarily agrarian and when the military was demobilized there was a baby boom and many of the returning troops moved to cities and created an economic boom- they had just seen the great big world - they weren't going back to the farm and the small lives they lived before. Europe was in need of a great many manufactured goods and we supplied a good portion of it and the US celebrated with new music, dance, fashion, ideals, and art - culturally America blossomed - a post war renaissance of sorts and to the victor goes the spoils attitude as artists, designers, musicians, composers, playwrights
In Europe, including Russia, there was chaos. The great Empires and Royal Lines of Rulers were gone: Russian, Austrio-Hungarian, German, Tsars, Emperors, Kaisers - ALL GONE. The Versailles treaty beggared and humiliated Germany. In Europe, manufacturing and agriculture were in a shambles and governments and industry were trying to figure out what to do and how to do it and did they have any authority anymore. Unemployment skyrocketed and discontent swelled and defeated countries licked their wounds and hardened their outlooks preparing for a future rematch. Russia became 4 socialist republics and morphed into the Soviet Union and with a reign of Terror the modern world had never seen before the USSR began it's methodical deliberate soul crushing brutalities on the people of the new Soviet Union - 4 soviets to start eventually expanding into 15 soviets, 16 if you count the Vory y zakone. The USSR had big construction plans even though they were overwhelmingly agrarian but the communists had stolen/liberated/accessed (pick whichever term speaks to you) unimaginable stores of vast wealth in natural resources - platinum and diamond mines not to mention timber cotton wheat coal oil and on an on. So, the Russian empire gone and the white army a fastly fading memory, the Red Army took control of all the military and because they had a new country to run, they didn't really demobilize in the way that the United States did - WWI was the war to end all wars and there was no reason to keep or train an army for future wars because there would never again be one. Simple. Wrong of course - less than 20 years later we would know that only the dead have seen an end to war - think it was George Santayana who wrote it in his Tipperary soliloquy but everybody else wants to say Plato - either way we learned the lesson - our American military demobilization was the last time the American people would ever be so naive regarding war. Maniacal madmen are a fact of life and we will stand an Army of Orwellian Rough Men at all times (the allusion I am making is to the quote by essayist Richard Grenier who wrote in 1993: "As George Orwell pointed out, people sleep peacefully in their beds at night only because rough men stand ready to do violence on their behalf.")
