Ideology and war.

War has been a universal and almost continuous human phenomenon from the earliest days of human life. The conduct of war until the modern era was mostly a matter for kings, emperors, chiefs, and their warriors. However, in the modern era, the Industrial Revolution, the Enlightenment, and the French Revolution (1789-1793) produced profound changes in the mobilization of populations in a political system for war. Ideas were coalesced into ideologies, which began to be used to motivate people to participate in all manner of causes. Such ideological causes seek to make great changes in the world that would be, according to some intellectual element in the ideology, “just” or “equal” or “national”—or whatever term was needed to mobilize the emotions of the masses.