Last time we saw that tribal societies based around corporate descent groups practicing horticulture for subsistence and living in permanent villages supplanted band societies based around fission-fusion in many parts of the world during the last 10,000 years. Like band societies, tribal societies were multi-level societies, with the tribe as its highest level.
Although tribes were bounded socio-linguistic entities, there was no overall leader of the tribe, no permanent hierarchy, and no centralized political institutions. Tribal societies were comprised of numerous segments—usually clans or villages—each of which controlled and managed its own affairs such as law and decision-making.
More food leads to more people, of course, yet tribal societies did not simply become bigger and bigger during the Neolithic. Rather, there were a lot fewer of them!
The anthropologist Robert Carneiro estimated that there were probably more than 100,000 independent political units (known as polities) at the start of Neolithic, with members averaging in the hundreds. Today there are only around 160 independent political entities on the planet according to the UN, give-or-take.  Many of those societies have millions of members each; two of them have over a billion. Even that understates the potential size of modern political entities; at one point, nearly 1 in 4 people on earth lived under the British Empire.
The formula is simple: as world population has grown, the number of independent political polities has decreased. Yet this negative correlation is counterintuitive: why aren't more independent polities created by segmentation of groups as their populations grow? 
Sometime during the Neolithic, after sedentary habitation patterns and cultivation had been around for thousands of years, larger societal units formed that overcame the innate tendencies toward political fragmentation. In order for this to occur, we had to overcome the natural size limitation inherent in human social groups. No one is quite sure exactly how this happened, but there has been a lot of speculation on the subject. But one thing we do know for sure is this was not caused by a voluntary mergers of formerly independent tribes.
To demonstrate this fact, Moffett describes the social dynamics of urban monkeys living in crowded human settlements where there is more food available due to rubbish heaps and feeding by tourists. Because of the additional food, the number of monkeys living in these urban areas is much larger than in the surrounding countryside, as you would expect. Yet the monkey troops themselves remain the same basic size—there are simply more of them in the cities than there are in the countryside!
Having more people requires more food. This self-evident truth makes it easy to assume that a sufficient supply of food is enough to spur the growth of societies. It is not.
Consider the monkeys clamoring around the marketplaces of New Delhi. Urban macaques live off the fruits (and meat and vegetables) of agriculture, stolen from street vendors.
While the relative plenty does indeed support a higher overall population of monkeys, urban troops nonetheless remain much the same size as those of their country bumpkin and deep-forest brethren. There are simply more troops, packed tightly as to leave no unoccupied space. (276)
Moffett argues that a similar dynamic was also at work in early human societies. In human societies, as with the monkey troops of New Delhi, there appears to be a natural size limitation of about 500 observed by anthropologists the world over, beyond which the tendency is to permanently fracture into multiple, smaller societies. New societies are constantly born while others die out.
For hundreds of millennia the volatility of human identities is what made the breakup of societies certain at a small size. Indeed that size was so predictable that some anthropologists have proclaimed 500 a "magic number." As a ballpark average for all parts of the globe, this was the number of people living in a band society. Much as 120 seems to be the size beyond which a chimpanzee community is likely to become unstable, it's reasonable to think that 500 represented an approximate upper limit on the population of a stable society for most of the prehistory of Homo sapiens.
One can infer a practical reason for a society to contain at least 500: by some calculations, a population of this magnitude gives humans the opportunity to select a spouse who isn’t a close relative.
My suspicion is that it's at about this population that the human wherewithal to have even the crudest knowledge of everyone in the society begins to be sufficiently strained for individuals to lean heavily on markers as a crutch in their interactions. In groups larger than 500, humans would start to feel truly anonymous, something that has no effect on ants but that undercuts people's desire to matter as individuals. (266-267)
In other words, with most animals, population growth alone leads to more societies, not bigger and bigger ones. Individual societies do not grow beyond the "natural" size limit for that species. Societal merging via osmosis does not take place.
Across the animals, the merger of societies is so rare as to be nearly nonexistent even in species where societies compete little. Bonobos and chimps exemplify this: the only "mergers" of their communities strain the word's meaning...Under ordinary conditions the same holds true among social insects: combining mature colonies isn't part of their pin-brained ethos. To my knowledge, the only permanent mergers of healthy societies take place only in African savanna elephants, and the rarely, and just between two cores that once belonged to a single core that divided in the past. (281-282)
Moffett notes that there is no record anywhere of tribal peoples integrating large numbers of foreigners into their society en masse. Why not? Because cultures are bounded entities. The markers of one culture would have invariably clashed with those of another.
The same is true of humans: once society members have their identity set in place, a merger freely made with another society is highly unlikely…The hurtle of merging societies is compounded in humans by the unliklelihood that each can adjust to the foreign identities of the other...So while bands of the same hunter-gatherer society could fuse, as could villages of a tribe, societies stayed firmly apart. (282)
Such clashing markers of identity kept different cultures in a perennial state of oil and water (or chalk and cheese). Even when tribal societies did form alliances, such as the Iroquois Federation of North America, or the Greek Amphictyonic League, the members' primary cultural identification remained with their original tribes:
Despite the human capacity for generating foreign partnerships, full mergers of societies are likewise never an outcome of alliances. Indeed, psychologists find that societies heavily dependent on each other are inclined to set themselves apart...Coalitions such as [the Iroquois confederacy] could be a source of pride, yet that didn't diminish the importance of their original societies...
Yet should a tribe have managed to retain a consistent identity, it still would never yield a sprawling civilization solely from the growth of its population. This would have been true even under the most ideal conditions—a favorable birth rate afforded by ample food and space, able leadership, and plenty of social differentiation. That these attributes were insufficient is demonstrated by the fact that all large human societies, on close inspection, contain not the descendants of a homogeneous stock of people, but populations of diverse heritage and identity.
Of this, then, we can be reasonably certain: societies, from the conjoined bands of hunter-gatherers to great empires, never freely relinquish their sovereignities to build a still greater society. (281-283)
Although cultural markers kept whole societies firmly apart, individuals could be integrated into another society, often as result of marriage or taking in the occasional refugee. However, when the stranger was admitted they would have taken on the cultural markers of their adopted tribe, or else have been regarded with curiosity at best; hostility at worst. Over a few generations, any cultural differences between outsiders and the majority would have gradually faded away.
The absorption of outsiders into human societies would not have begun with aggression. It started—harmlessly enough considering that both sides in the arrangement could benefit—with the acceptance of the occasional outsider as a member, as is necessary for finding sex partners in many species.
While band societies tended to be populous enough to find members to choose a mate from among themselves, some transfers would have taken place to seal a partnership between groups and to minimize inbreeding over long spans of time...Nevertheless, given how people nurture their identities in the face of contact with outsiders, a newcomer would have had little effect on society's conduct...adding an outsider or two in this manner wasn't remotely sufficient for anything remotely close to an entire ethnic group to materialize. (283-284)
Moffett argues that the first incidence of incorporating large numbers of foreigners into a society at a scale greater than adding the occasional new member now and then was slavery.
As we saw earlier, band societies comprised of hunter-gatherers have no motivation to keep slaves. Bands worked together as a "factory" to procure whatever they needed for themselves. Small-scale societies based around fission-fusion would not have had the capacity to keep captives in bondage for long periods of time.
But once groups became permanently anchored to one spot and started producing their food on a regular basis, there was a motivation to have others do that hard work for you. Keeping slaves now made more sense from a work/reward perspective. Slaves provided unskilled labor, allowing the native inhabitants to specialize in other areas, such as warfare, handicrafts, or political leadership. They also provided a ready-made underclass for inhabitants of the society to look down upon which kickstarted the impetus towards class stratification.
Moffett notes that slave taking appears to be an exclusively human activity. While there are slavemaker ants, their societies are so radically different from our own as to strain the comparison. The closest primates come is chimps temporarily detaining a female for sex (i.e. gang rape) or baby-stealing among langur monkeys.*
It was slavery, Moffett contends, that first provided the initial template for integrating larger numbers of foreigners into a community beyond just a few isolated individuals like spouses, prisoners or occasional refugees:
An unpleasant truth is that ethnicities made their nascent appearance by way of an industry that didn't make headway except among people who had settled down: slavery...The very existence of slavery required a society's social boundaries to expand to allow for their numbers and strangeness, a radical achievement... Indeed, by their mere presence slaves made the inclusion of outsiders in substantial numbers a comprehensible notion.
However, the question remains how societies came to engulf entire populations and consider them as fellow members... (284-287)
While slavery provided the initial template for incorporating large numbers of foreigners into a society on a permanent basis, the merging of whole societies was a result of increasing conflict between societies. Ultimately, these conquests and absorptions came about due to increasing population pressure and the gradual elimination of unoccupied territories, both results of increasing intensification.
In band and tribal societies, conflicts with rival groups would have been resolved either by killing or (more often) fleeing. There was no motivation to permanently occupy another territory or wipe out an entire tribe. Skirmishes observed between modern hunter-gatherers generally end after each side has lost a few members, whereupon the combatants retreat to their home base.
Cautious raids made sense for hunter-gatherer and tribal peoples, since they could afford to lose few fighters and the aim was to inflict damage or kill rather than subjugate. Big Men…often had to personally lead warriors in order to motivate and sustain their following… (296)
When societies started settling down in circumscribed territories and living in permanent settlements rather than mobile camps, the stakes were raised. Settled hunter-gatherers made large investments in the landscape; horticulturalists intensified production to an even greater degree; agriculturalists still further. Such large-scale investments in the landscape could no longer be easily abandoned when threatened. There was no longer any "empty space" to flee to. From 10,000 B.C.E to C.E. 1 the human population increased a hundredfold.
As population size and density accelerated due to horticulture and farming, societies increasingly began rubbing up against one another, leading to friction. Enough friction generates sparks, and eventually, fires break out. Archaeological evidence has shown that conflicts between groups intensified at the onset of the Neolithic. We see increasing signs of violence between groups instead of sporadic raiding and occasional homicides—for example defensive structures such as walls and pallisades start to be built around villages in certain parts of the world. Once dense populations accumulated substantial wealth and material resources due to intensification—things like private property, storehouses, and permanent structures—they had to defend it from greedy neighbors.
Rather than exterminating vanquished tribes, it made much more sense for a victorious population to keep as many of them alive as possible and turn them into slaves. Eventually, instead of enslaving them, the conquering population would have left the subjugated populations in place and required them instead to turn over a substantial part of their accumulated wealth on a regular basis. The subjugated population would be seen as in debt to their overlords, since they would otherwise be dead. The tribute was a way of paying off that debt.
What started the process along was a change in the motivation for warmongering... once people began to live in anything larger than band societies that could fall apart after repeated raids, completely destroying a foreign group was seldom either the goal or the outcome of clashes in the past...Wiping people out makes no sense given the incentives to profit from a conquered population.
Much as enslavement can prove economically more lucrative that killing people, subjugation applied that calculus to taking in entire societies, from which tribute or labor could be extracted on a continuing basis...Although taking someone's land, let alone the people on it, would rarely have occurred to nomadic hunter-gatherers, tribal societies found that the spoils of a fight could be multiplied manyfold when a pugnacious group annexed a productive territory and let its residents live. (287-288)
This is known as the Tributary Mode of Production. In this mode, a dominant group of people extracts surpluses from a subjugated population under the ongoing threat of potential violence. The dominant group in turn protects the subjugated group from others who may wish to prey on them. Eric Wolf describes the tributary mode of production as:
...a mode of production in which the primary producer, whether cultivator or herdsman, is allowed access to the means of production, while tribute is exacted from him by political or military means.
In other words, social labor is, under these conditions, mobilized and committed to the transformation of nature primarily through the exercise of power and domination—through a political process. Hence, the deployment of social labor is, in this mode, a function of the locus of political power; it will differ as this locus shifts position. p. 80
The societies that accomplished this feat were larger and much more politically organized than tribes. As we saw earlier, tribal societies could summon more warriors to fight in battle than band societies could due to the existence of corporate kinship groups and ancestor worship. While tribes could unite on occasion for purposes of attack or defense, there was no permanent political apparatus or power structure to unify all the different the segments. However, when a segmentary society did manage to unite under permanent—often hereditary—leadership, these societies became known as chiefdoms, and their leader, a chief. In chiefdoms political power became centralized in the person of the chief and his associated household. Leadership becomes permanently manifested in the office of the chief rather than informal and ad hoc leadership.
Chiefdoms are another level of complexity above tribal societies. They are an outgrowth of kinship-based societies in which one particular group—the highest ranking lineage in a conical clan, for example—gains hegemony over all the others. This lineage then goes on to construct a permanent apparatus of political and social control through the use of strategic marriages, political alliances, ownership of essential resources, displays of prestige goods, making loans, managing long distance trade, and so forth. The leader of this lineage becomes the chief, with access to coercive power, often derived from his prowess in battle. Because chiefdoms were an outgrowth of kinship-based societies, leadership positions were based around kinship relations, and therefore passed down in families unlike in band societies—something anthropologists refer to as ascribed status (in contrast to the achieved status of a Big Man).
A Big Man could become a chief by taking control of other villages. That didn't always happen by seizing enemies. At times he strong-armed a permanent union from what had been originally been a fair alliance between friendly autonomous villages, put together to serve the needs of the moment in combating a common adversary.
Such a predatory individual could then commandeer the whole region as a base to further expand his domain. Vigorous chiefdoms came to take over what had once been many independent villages, and eventually entire other chiefdoms, to attain populations in the tens of thousands or more. (289)
Moffett portrays chiefdoms as a major watershed in human societal evolution, due to the ability of chiefdoms to centralize authority and incorporate disparate human populations into an greater whole. This, in turn, allowed societies to grow much larger than was possible in segmentary societies. Tribal societies still remained the predominant social form in many remote parts of the world, however.
In a band and village society, the constituent villages and bands had been fully able to act on their own and did so most of the time. With chiefdoms, such loose connections between the populations of a society became a thing of the past. Chiefdoms were thus a formative step in a consolidation of societies into a unit—a litmus test for what we think of as a sturdy nation today. (290)
Chiefdoms were a turning point as pivotal to the advance of societies as was the evolution of markers of identity. No civilizations would exist without the pattern set in motion by chiefdoms after the Neolithic Revolution: the subjugation of foreign societies rather than routing, ruining, enslaving, or murdering them...
Chiefdoms were never more than a minority of societies. Still, European explorers came upon chiefdoms by the hundreds, some with many thousands of subjects... (288-289)
Top down command-and-control systems are obviously more militarily effective then acephalous groups of warriors with no clear plan ("apes together strong"). Thus, chiefdoms with a greater degree of hierarchical organization had a clear advantage over more loosely-organized confederations of tribes or clans. Segmentary societies that do not have the organizational capacity to reset aggression from expansionist societies either "scale up" to become chiefdoms, or are absorbed by them. This was described as The Parable of the Tribes by Andrew Bard Schmookler:
I have just outlined four possible outcomes for the threatened tribes: destruction, absorption and transformation, withdrawal, and imitation. In every one of these outcomes the ways of power are spread throughout the system. This is the parable of the tribes.
As stronger societies swallowed weaker ones, some sort of repressive apparatus had to be put in place to manage the subjugated populations. In the beginning, this setup would have been seen as a great boon to the conquering society. The members of the dominant group would have become much richer overall. However, once such a repressive apparatus had been put in place by the chiefs and consolidated, it would have increasingly been applied internally as well by the ruling class. It would also have become more permanent. This would have proceeded gradually, with the native population barely aware that it was happening initially. Over time, people would have willingly surrendered their freedoms for the increased wealth and security. Eventually, power would become consilidated in the hands of the chief and his retinue. This process leads to a truism observed throughout human history even in the most modern industrialized societies: conquest abroad leads to repression at home.
Maintaining control of many people, especially when they belong to multiple groups, has always been a laborious business. For an expanding chiefdom to continue functioning, the defeated, though they might be dehumanized to an extent, couldn't be denigrated as slaves. Their former identity was not entirely lost to them. Many remained on their land with family and community, a situation that allowed their populations—unlike those of most slaves—to increase....Yet life in a chiefdom could be tough...Once conquered...the vanquished may have been a step up from slaves, but they were still often regarded much like resources to be exploited...Compounding the rapacity of chiefdoms was the demand for resources by an expanding part of the society, from priests to artists, disconnected from food production altogether. (290)
In chiefdoms and the first small states, the mingled populations wouldn't have been what we consider ethnicities and races today. The differences in identity between the conquerors and the subjugated would have been minimal to none. More than likely they were merely adjacent villages of the same tribe, once autonomous but now politically fused.
Expand enough, though, and a chiefdom or state society would take in not only peoples of distinct societies but groups defined by distinct languages and traditions. Marked differences presented challenges for communication and control, yet had their advantages: the subjugated were unambiguously other and could be treated as such. There was less moral imperative to be concerned with the newcomers' welfare...(310)
...To endure for generations, societies starting with chiefdoms needed to achieve what is impossible in other species: a sustained tolerance, if not melding, of groups that had formerly been distinct. Perhaps counterintuitively, then, this formation-of-the-whole was strongest not in societies whose members were most alike, but in those where people of varied origins came to coexist and depend on each other. This was notably true for the state societies that would rise from the most lavishly successful chiefdoms...(290)
Chiefdoms are typically classified into two major categories: simple and complex. A simple chiefdom has one level of authority: the chief; a complex chiefdom has multiple levels of authority in the persons of subordinate chiefs loyal to a single paramount chief.
Chiefdoms are additionally referred to by anthropologists as ranked societies. Ranked societies are not egalitarian; rather, there is an established pecking order for both individuals and clans. Those in the higher ranks have disproportionate control over tribal resources compared to others:
In relative rank societies, persons and lineage groups can be ranked relative to each other, but there is no absolute highest point of the scale. In most groups, moreover, sufficient uncertainty and argument exist for relativities to be ultimately inconsistent with one another. Rank will be contested.
In absolute rank societies, an absolute, highest point emerges. A chief or paramount chief is accredited uncontested highest rank, and all other ranks' lineages are measured in terms of their distance from his. This is usually expressed ideologically in terms of his descent from the ultimate ancestors, perhaps even the gods, of the group. So one characteristic institution appears: a ceremonial center, devoted to religion, controlled by the chief's lineage. From this centralized institution onward to the state is only a step. 
Anthpologists Kent Flannery and Joyce Marcus argue that absolute rank societies emerged when one particular group or lineage achieved a monopoly over ritual authority and used this to manipulate the "social logic" of the tribe. They note that absolute rank societies tend to have formalized ritual specialists—i.e a priesthood—who control access to supernatural forces such as gods and ancestral spirits. The priesthood becomes the link between the invisible world of the spirit and the world of coarse matter that we mortals inhabit here on earth. Thus imaginary concepts derived from supernatural ideas that were used to regulate social relationships in acephalous societies—concepts such as sharing and justice—would instead be used to rationalize their opposite.
When we look at hunters and gatherers, we see a dominance hierarchy as clear as that of chimpanzees. It is, however, a hierarchy in which the alphas are invisible supernatural beings, too powerful to be overthrown by conspiracy or alliance, and capable of causing great misfortune when disobeyed. The betas are invisible ancestors who do the bidding of the alphas and protect their living descendants from harm. The reason human foragers seem, superficially, to have no dominance hierarchy is because no living human can be considered more than a gamma within this system.
...[A]s we watch inequality emerge in human society...[w]e will see would-be hereditary leaders who attempt to link themselves to revered ancestors or even to supernatural beings. By the time we reach the civilizations of Egypt and the Inca, we will be introduced to kings who actually claimed to be deities. Such strategies for justifying inequality would not have worked if humans did not already consider themselves part of a natural/supernatural dominance hierarchy.
The celestial alphas were the source of the ultimate sacred propositions. Our beta ancestors were the focus of many rituals. The emotions of living gammas made possible the awe-inspiring experience...Thus the concept of the sacred, which had once strengthened human society by encouraging selflessness and reducing status confrontation, would one day be manipulated to create a hereditary elite. 
No one is quite sure how and why chiefdoms first arose out of segmentary tribal societies, but there are two major schools of thought on the subject: functionalist (or managerial or adaptionist) theories, and conflict (or coercive or militarist) theories.
Functionalist theories argue that chiefdoms first arose to carry out some sort of basic function.
As societies grow larger and have greater impacts on their surrounding environment, and as economic activities become more diverse and highly specialized, they inevitably run into collective action problems. Some sort of centralized authority is required to deal with these collective action problems: "Thus, the chief emerges as the organizer of production and exchange where there is a high level of investment in collective labor." 
An example is coordinating production and distribution of staple goods in societies that a.) Have a lot of different occupational specialties; b.) That occupy large swaths of territory with a wide variety of different ecosystems (coasts, plains, mountains, forests, wetlands, etc.); and c.) That need to maintain large-scale public investments in the landscape. Another example is the management of surplus storage to tide people over during periods of scarcity. So-called "Liberal theories," which emphasize the economic benefits of the state—especially with regards to private property—can be classified as functionalist theories. The need to defend one's territory from outsiders could fall under either functionalist or conflict theories depending on how you want to classify it.
In other words, chiefdoms evolved to solve coordination problems that arose in increasingly dense and complex societies with greater degrees of economic specialization. These societies had a need for political integration beyond that of the local village or corporate group. Allen Johnson and Timothy Earle list these as: (1) to reduce production risks, (2) to manage resource competition, (3) to allocate resources efficiently and to make capital investments, and (4) to conduct interregional trade. As the early anthropologist Bronislaw Malinowski wrote of chiefs:
Throughout the world we would find that the relations between economics and politics are of the same type. The chief, everywhere, acts as the tribal banker, collecting food, storing it, and protecting it, and then using it for the benefit of the whole community. His functions are the prototype of the public finance system and the organization of state treasuries of today. Deprive the chief of his privileges and financial benefits and who suffers most but the whole tribe? 
Coercive, or political economy theories emphasize the fact that people rarely give up cherished freedoms voluntarily or freely submit to centralized control, even in return for hypothetical potential benefits. Instead, these theorists argue that chiefdoms mainly came about through conflict—either military conflicts between societies, or conflicts between different classes within a society. Marxist theories can thus be classified as conflict theories.
These theorists argue that once certain key resources fall under the control of elites, they can then utilize that control over resources to dominate other segments of society. Resistence to emerging despotic power meant being cut off from essential resources like land and water, and so the rest of the tribe had no choice but to submit to elite control:
Control over the economy is direct and material power over the lives of people. Individuals and housholds must obtain the food and goods necessary for their survival. They must eat daily to survive, and they must obtain clothing, housing and craft goods routinely. Humans exist in a world of energy flows that sustain all life, including their own…
Coercive, political theories of social evolution, based on a critique of the adaptationist theories, emphasize that individuals and groups do not give up autonomy except when compelling power is exerted to make them submit. Control over factors of production, distribution or consumption provides the mechanism for amassing power. To the degree that the economy is essential to human survival, control over the economy yields direct control over people's lives. This control need not, however, be all-inclusive; it is often selective, based on dominating particular parts of the economy...
The flow of things through an economy is like an irrigation system. Tapped from natural flows, the water is diverted through built channels to water fields of choice. To the degree that the chief builds and controls the flow, he determines what flourishes and what perishes. Chiefly control over critical nodes of distribution in the material flows of the economy translates into control over the many fields of political action. 
One of the earliest of these theories was the "Hydraulic Theory" of Karl Wittfogel. Wittfogel argued that the need to build and maintain large-scale irrigation works in regions which relied heavily upon irrigation water for farming led to the establishment of professional managers to supervise the construction and maintenance of such waterworks. These professional managers eventually came to be the ruling class. Because water provided by the canals was required to grow crops, the commoners had no choice but to submit to the rule of these elites or starve—what he referred to as "Oriental Despotism." This theory has generally fallen out of favor, although variants of it still have their adherents.
The related conflict, or militarist theories center mainly around the use of violence, both internally and externally. In these theories, chiefdoms arise to more effectively defend themselves against external aggressors or to conquer their weaker neighbors. Leaders are typcially warlords, and their power comes from their specialization in the art of violence: "Chiefdoms are characterized by endemic warfare and the rise to power is always implictly military at its roots." 
In these theories, the desire to conquer subject peoples and to secure ongoing tribute from them is the major rationale for the existence of chiefdoms, with the managerial functions of leaders as an afterthought. Early versions of the theory argued that chiefdoms and early states exclusively came into existence when one group of people conquered another, as expressed by the sociologist Franz Oppenheimer:
The state, completely in its genesis essentially and almost completely during the first stages of its existence, is a social institution forced by a victorious group of men on a defeated group, with the sole purpose of regulating the dominion of the victorious group over the vanquished, and securing itself against revolt from within and attacks from abroad. 
More mature versin of the theory married these two elements, emphasizing the subsequent economic benefits that came about due to the centralization of political power in order to wage war:
All these writers are expressing variants of the same view: The state originated in warfare, but human evolution carried it onward to other pacific functions. In this refined model, military conquest settles down into a centralized state. Military force is disguised as monopolistic laws and norms administered by a state. Though the origins of the state lie merely in military force, it subsequently develops its own powers. 
This theory would seem to explain why people acquiesce to despotic power: they have no choice! However, this theory also has its problems. The most salient is the chicken-and-egg problem. A militarily expansionist society presupposes some degree of centralized control; but if centralized control is a result of military conquest, how can it also be a cause?
Anthropologists generally classify the sources of chiefly power into three major categories: economic, military, and ideological. The degree to which these three factors played a role in securing chiefly power varied from society to society depending on what the particular material conditions of that society were. In some cases, control over economic resources by chiefs was paramount, while in others warfare played a greater role**.
All chiefdoms instituted an ideology that justified differential access to authority and the ownership of productive resources by the ruling class: "Ideologies are systems of belief created and strategically manipulated by certain social segments, most notably the ruling elites of chiefdoms and states, to establish and maintain the legitimacy of their position in society." 
Anthropologist Timothy Earle emphasizes what he calls the materialization of a ruling ideology: "The materialization of ideology transformed the legitimizing beliefs of the ruling elite into concrete cultural things that could be controlled through the labor process within the local community."  This included not just physical objects like pyramids, temples, and monuments, but also more ephemeral things like public ceremonies, feasts, and ritual activities.
Chiefs were not priests; they were generalized leaders, seamlessly combining economic, military, and religious power. At different moments, chiefs acted as managers, warriors, and ritual specialists. Much of the competitive arena of chiefdoms involves fights over different sources of power and attempts to bring these sources together. Even within a specific medium of power, such as ideology, control was often problematic and multiple, partially overlapping power strategies were created. Thus chiefdoms were often characterized by very complicated and fractured institutions of power—heterarchies, as opposed to heirarchies. 
Earle and Johnson argue that chiefdoms were distinguished most of all by social stratification, which sociologist Michael Mann defined as "the permanent, institutionalized power of some over the material life chances of others."  They note that, "Chiefdoms are based on generalized central leadership, as are Big Man societies, but a chief has sufficient institutionalized control over his society's policial and economic organizations to be able to restrict leadership to an elite segment."  They attribute this ability to restrict access to power and resources by elites as coming about due to one of four major factors:
1.) The establishment of central storage facilities which were originally instituted as a way of managing risk but provided control over capital by elites for use in political affairs;
2.) Investments in large-scale production technologies which made harvests more relaible and efficient but which bound subsistence producers to chiefs;
3.) Warfare in naturally circumscribed environments, which required centralized military leadership but allowed victorious chiefs and their allies to control a subjugated population; and
4.) Long-distance foreign trade which was not open to commoners because of the high costs of transport and the difficulties of establishing and maintaining inter-societal ties. 
Although the emergence of ranked societies occurred independently all over the world, only in a few select parts of the globe did these factors combine to form societies that were even more complex and stratified than chiefdoms—societies that we generally refer to as states. So-called "pristine" states† typically formed in alluvial regions dependent on cereal agriculture which were adjacent to steppe frontiers inhabited by nomadic peoples. Such societies were also usually emmeshed in intereconnected webs of trade with distant societies for luxury goods.
These incipient states experienced rapid growth—both economic and demographic—after about 5,000 BCE. That growth, in turn, allowed greater investment opportunities on the part of elites who were able to achieve centralized control over large geographical areas and establish a permanent ruling class. In their greater organizational capacity and insatiable desire for expansion, states and later empires would scale up far beyond any chiefdom in an autocatalytic process, gobbing up whole societies like bacteria expanding in a petri dish in their never-ending quest for growth.
That's what we'll talk about next time.
* Both of these behaviors are sadly also present in our own species.
** For example, Timothy Earle writes of the Wanka chiefdoms of the Upper Mantaro Valley, Peru:
The late Wanka chiefdoms were evidently based largely on military power—a need for common defense and the subjugation of neighbors following negotiated surrender. People entered the larger Wanka confederacies though fear and intimidation. The political power of the Wanka chiefs rested almost exclusively on their military might. (How Chiefs Came to Power, p. 116)
Compare that to the chiefdoms of Hawai'i:
Prior to the island's incorporation with the world mercantile economy, power in the Hawaiian chiefdoms came to rest firmly on the foundation of the intensive irrigation economy. The facilities and te land-tenure system that they materialized were a consistent and strong form of economic control upon which other sources of power could be assembled. Surplus mobilized through the agriculture systems supported a warrior elite and the materialized ideology of cheifly rule. (How Chiefs Came to Power, p. 89)
† I prefer the term bootstrap states, after the computer science concept of bootstrapping, but we'll see if that catches on.
All quotations in parantheses from The Human Swarm by Mark W. Moffett; Basic Books, 2019. Emphasis mine.
 Allen W. Johnson and Timothy Earle: The Evolution of Human Societies: From Foraging Group to Agrarian State, p. 245. Standford University Press, 2000.
 Eric R. Wolf: Europe and the People Without History, p. 80
 Michael Mann: The Sources of Social Power: Volume 1, A History of Power from the Beginning to AD 1760; p. 37
 Kent Flannery and Joyce Marcus: The Creation of Inequality: How Our Prehistoric Ancestors Set the Stage for Monarchy, Slavery, and Empire; pp. 69-74
 Michael Mann: The Sources of Social Power: Volume 1, A History of Power from the Beginning to AD 1760; p. 60
 Quoted in Mann, p. 60
 Timothy Earle: How Chiefs Came to Power: The Political Economy in Prehistory; pp. 67-70
 ibid., pp. 203-204
 ibid., p. 8
 Quoted in Mann, p. 54
 ibid., p. 55
 Allen W. Johnson and Timothy Earle: The Evolution of Human Societies: From Foraging Group to Agrarian State; p. 259
 Timothy Earle: How Chiefs Came to Power: The Political Economy in Prehistory; p. 192
 ibid., pp. 150-151
 Michael Mann: The Sources of Social Power: Volume 1, A History of Power from the Beginning to AD 1760; p. 38
 Johnson and Earle; pp. 302-303
I had to rush this one out because I realized that the Chiefs will be appearing in the Super Bowl this weekend. Finally, some serendipitous timing! Although in real life, actual buccaneers—like band societies—were quite egalitarian in practice and may have even contributed to the rise of modern democracies.
As for me, I'll be chilling this weekend. And that's not a figure of speech—it's not supposed to get above the teens Fahrenheit for at least the next couple of weeks, and I'm just so very, very cold :( Calgon, take me away! Hopefully things are better where you are.