A government, according to the famous characterization by the sociologist Max Weber, is an institution that holds a monopoly on the legitimate use of violence. Governments, then, are institutions that by their very nature are designed to carry out violence. Ideally this violence is held in reserve as a deterrent to criminals and invaders, but for millennia most governments showed no such restraint and indulged in violence exuberantly.

All of the first complex states were despotisms in the sense of an "exercised right of heads of societies to murder their subjects arbitrarily and with impunity." Evidence for despotism, Laura Betzig has shown, may be found in the records of the Babylonians, Hebrews, Imperial Romans, Samoans, Fijians, Khmer, Natchez, Aztecs, Incas, and nine African kingdoms. Despots put their power to good Darwinian use by living in luxury and enjoying the services of enormous harems. According to a report from the early days of the British colonization of India, "a party given by the Mogul governor of Surat… was rudely interrupted when the host fell into a sudden rage and ordered all the dancing girls to be decapitated on the spot, to the stupefaction of the English guests." They could afford to be stupefied only because the mother country had recently put its own despotism behind it. When Henry VIII got into various of his bad moods, he executed two wives, several of their suspected lovers, many of his own advisors (including Thomas More and Thomas Cromwell), the Bible translator William Tyndale, and tens of thousands of others.

He who lives by the sword dies by the sword, and in most of human history political murder -- a challenger killing a leader and taking his place -- was the primary mechanism for the transfer of power. A political murderer differs from the modern assassin who tries to make a political statement, wants to go down in the history books, or is stark raving mad. Instead he is typically a member of the political elite, kills a leader to take over his position, and counts on his accession to be recognized as legitimate. Kings Saul, David, and Solomon were all targets or perpetrators of murder plots, and Julius Caesar was one of the thirty-four Roman emperors (out of the total of forty-nine that reigned until the division of the empire) who were killed by guards, high officials, or members of their own families. Manuel Eisner has calculated that between 600 and 1800 CE, about one in eight European monarchs was murdered in office, mostly by noblemen, and that a third of the killers took over the throne.

The power of despots to kill on a whim is the backdrop to stories told throughout the world. The wise King Solomon proposed to resolve a maternity dispute by butchering the baby in question. The backdrop to the Scheherazade story is a Persian king who murdered a new bride every day. The legendary King Narashimhadev in Orissa, India, demanded that exactly twelve hundred artisans build a temple in exactly twelve years or all would be executed. And in Dr. Seuss's The Five Hundred Hats of Bartholomew Cubbins, the protagonist is nearly beheaded for being unable to remove his hat in the presence of the king.

By the 17th and 18th centuries, many countries had begun to cut back on tyranny and political murder. Between the early Middle Ages and 1800, Eisner calculates, the European regicide rate declined fivefold, particularly in Western and Northern Europe. A famous example of this change is the fate of the two Stuart kings who locked horns with the English Parliament. In 1649 Charles I was beheaded, but in 1688 his son James II was deposed bloodlessly in the Glorious Revolution. Even after attempting to stage a coup he was merely forced into exile. By 1776 the American revolutionaries had defined "despotism" down to the level of taxing tea and quartering soldiers.

Political leaders not only kill each other, but commonly commit mass violence against their citizenries. They may torture them, imprison them, execute them, starve them, or work them to death in pharaonic construction projects. Rummel estimates that governments killed 133 million people before the 20th century, and the total may be as high as 625 million. So once raiding and feuding have been brought under control in a society, the greatest opportunity for reducing violence is reducing government violence.

At the same time that governments were gradually becoming less tyrannical, thinkers were seeking a principled way to reel in government violence to the minimum necessary. It began with a conceptual revolution. Instead of taking government for granted as an organic part of the society, or as the local franchise of God's rule over his kingdom, people began to think of a government as a gadget -- a piece of technology invented by humans for the purpose of enhancing their collective welfare. Of course, governments had never been deliberately invented, and they had been in place long before history was recorded, so this way of thinking required a considerable leap of the imagination. Thinkers such as Hobbes, Spinoza, Locke, and Rousseau, and later Jefferson, Hamilton, James Madison, and John Adams, fantasized about what life was like in a state of nature, and played out thought experiments about what a group of rational actors would come up with to better their lives. The resulting institutions would clearly bear no resemblance to the theocracies and hereditary monarchies of the day. It's hard to imagine a plausible simulation of rational actors in a state of nature choosing an arrangement that would give them the divine right of kings, "L'état, c'est moi," or inbred ten-year-olds ascending to the throne. Instead, the government would serve at the pleasure of the people it governed. Its power to "keep them all in awe," as Hobbes put it, was not a license to brutalize its citizens in pursuit of its own interests but only a mandate to implement the agreement "that a man be willing, when others are so too… to lay down this right to all things; and be contented with so much liberty against other men, as he would allow other men against himself."

It's fair to say that Hobbes himself didn't think through the problem deeply enough. He imagined that somehow people would vest authority in a sovereign or a committee once and for all at the dawn of time, and thereafter it would embody their interests so perfectly that they would never have reason to question it. One only has to think of a typical American congressman or member of the British royal family (to say nothing of a generalissimo or a commissar) to see how this would be a recipe for disaster. Real-life Leviathans are human beings, with all the greed and foolishness we should expect of a specimen of Homo sapiens. Locke recognized that people in power would be tempted to "exempt themselves from the obedience to the Laws they make, and suit the Law, both in its making and its execution, to their own private Wish, and thereby come to have a distinct Interest from the rest of the Community, contrary to the end of Society and Government." He called for a separation between the legislative and executive branches of government, and for the citizenry to reserve the power to throw out a government that was no longer carrying out its mandate.

This line of thinking was taken to the next level by the heirs of Hobbes and Locke who hashed out a design for American constitutional government after years of study and debate. They were obsessed with the problem of how a ruling body composed of fallible humans could wield enough force to prevent citizens from preying on each other without arrogating so much that it would become the most destructive predator of all. As Madison wrote, "If men were angels, no government would be necessary. If angels were to govern men, neither external nor internal controls on government would be necessary." And so Locke's ideal of the separation of powers was written into the design of the new government, because "ambition must be made to counteract ambition." The result was the division of government into executive, judicial, and legislative branches, the federalist system in which authority was divided between the states and the national government, and periodic elections to force the government to give some attention to the wishes of the populace and to transfer power in an orderly and peaceable way. Perhaps most important, the government was given a circumscribed mission statement -- to secure the life, liberty, and pursuit of happiness of its citizens, with their consent -- and, in the form of the Bill of Rights, a set of lines it could not cross in its use of violence against them.

The forms of democracy that were tried out in the 18th century were what you might expect of the 1.0 release of a complex new technology. The English implementation was weak tea, the French implementation an unmitigated disaster, and the American implementation had a flaw that is best captured in the actor Ice-T's impression of Thomas Jefferson reviewing a draft of the Constitution: "Let's see: freedom of speech; freedom of religion; freedom of the press; you can own niggers… Looks good to me!" But the value of the early designs for democracy was their upgradability. Not only did they carve out zones, however restricted, that were free of inquisitions, cruel punishments, and despotic authority, but they contained the means of their own expansion. The statement "We hold these truths to be self-evident, that all men are created equal," however hypocritical at the time, was a built-in rightswidener that could be invoked to end slavery four score and seven years later and other forms of racial coercion a century after that. The idea of democracy, once loosed on the world, would eventually infect larger and larger portions of it, and as we shall see, would turn out to be one of the greatest violence-reduction technologies since the appearance of government itself.

Yet another innovation of the American system was its explicit recognition of the pacifying effects of positive-sum cooperation. The ideal of gentle commerce was implemented in the Commerce, Contract, and Takings clauses of the Constitution, which prevented the government from getting too much in the way of reciprocal exchanges among its citizens.