Three Wars that could not have been lost without turning the world upside down. Which one is easiest to imagine having lost, without fighting again? Civil War, probably the easiest of the 3 to imagine. The South may have been forced to change over time even if they had won at the time. World War II. I suppose, it's conceivable to imagine Germany developing the A-Bomb first. They hang it as a threat over the US and never invade here. We become isolated, but accepting that Germany rules almost all of the rest of the world. Revolutionary War. Close to impossible to imagine. I suppose the scenario requires a huge occupying force from England where the sheer numbers prevent a successful uprising. Any of the 3, try to imagine, not pretty.