The American Civil War was truly one of the first 'modern' wars, in that it brought the idea of a total war: one that crippled the civilian populace of the enemy, and utilized new technologies that would later be used and improved upon in future wars.
Could a total war strategy been implemented in a war before 1800? Technically, the Thirty Years' War could count, but it was mostly chaos and anarchy that brought about much of the destruction.