 Everyone is worried about the downfall of civilisation and the rise of barbarism. The left sees Trump as a retrograde menace to the diverse and inclusive society of their hopes and dreams. They use the hashtag resist and chant, he will not divide us. Those most radicalised against Trump call themselves anti-fa, anti-fascists, and pose as the vanguard of the resistance against an incipient return of Nazi-like savagery. Trumpists, on the other hand, see their man as a stalwart defender of western civilisation against the barbarians at the gates. His most radicalised fans have embraced hard nationalism, the alt-right, neo-reaction, etc., and fancy themselves to be modern crusaders. Trump himself is especially concerned with the ravaging brutes offering to sell us flat-screen TVs. In his inaugural address, he said, We must protect our borders from the ravages of other countries making our products, stealing our companies and destroying our jobs. Which side truly champions civilisation and which threatens it? To answer this meaningfully, we must first understand what civilisation is. The word civilisation ultimately derives from civitas, the Latin word for city. In a sense, civilisation is the way of life of the citizen, or city denizen. And the most distinctive and fundamental feature of city life is its economic aspect. Plato explored the essential characteristics of the city in the Republic. He asked, what are the economic rudiments of a city-state? Most essential, he answered, is the provision of the citizenry's bodily requirements, the bottom level of Abraham Maslow's hierarchy of needs pyramid. Humans need food to sustain their life, as well as shelter and clothing to protect them from the elements. Plato then asks, should each individual provide all three for himself and his family? That is the mode of provision typical of the world outside the city. Some families, clans and tribes, whether hunter-gatherers, nomads or peasants, produce everything they use. Such economic isolation is called autarchy. But according to Plato, each citizen would be better off if the work were divided, if each citizen specialised. One might be a farmer, another a builder, another a weaver. The farmer produces food not only for himself, but for the builder and the weaver. The builder produces shelter not only for himself, but for the farmer and the weaver. And the weaver produces clothing not only for himself, but for the farmer and the builder. Why this division of labour, as Adam Smith would call it centuries later? Because as both Plato and Ludwig von Mises agree, human beings are diverse in their productive capacities. Some are better suited to farm, others to build, still others to weave. If the best farmers kept their hands to the plough, the best builders stayed in their wheelhouse and the best weavers stuck to their knitting, then more shake-shack burgers, trendy lofts and Spank's leggings would be produced than if everybody had to do all three. But what if the best at all three jobs happened to be the same person? Even then it would be in the interest of each individual to divide their labour, as explained first by the classical economists James Mill and David Ricardo, by expounding the law of comparative advantage. For example, below the Spank's headquarters in Atlanta is a shake-shack. For all I know, Spank's founder Sarah Blakely might be a better cook than the teenager at the grill downstairs. The billionaire could take the time to source and make her own shack burger. But doing so would come at the expense of instead dedicating that time to minding her undergarment empire. If Sarah works on Spank's business during that time, she'll probably produce so much value for her customers that they will pay her enough money to buy as many shack burgers as she could ever want and much more besides. So it makes sense for Sarah to specialise in her field and to leave food production to shake-shack and others, to spend her working hours on clothing and pop downstairs whenever she craves a burger for lunch. In economic terms, even though Sarah might have an absolute advantage in producing both undergarments and burgers, the fry cook has a comparative advantage in producing burgers. Back to Plato, who then extended the logic for specialisation beyond the production of consumer goods to the production of capital goods. The individual whose comparative advantage is in using a plow shouldn't waste good plowing time in making one. He should focus still further on farming and let others specialise in producing the implements of agriculture, Plato argued. Neither will the builder make his tools, as an isolated peasant does, he continues, nor any other producer of goods of the first order, as Austrian economist Karl Menge called them. Instead in the city you will find abundant artisans, manufacturing what Menge called goods of higher orders, carpenters making plows, smiths making saws, etc. The efficiencies of the division of labour further extend to the specialised production not only of tools but of components, which are also higher order goods. Thus the amazing productivity of Henry Ford's assembly line. Moreover, the making of a single tool or component can be further divided into multiple subtasks, each performed by specialists to extract even more efficiency, as Adam Smith illustrated in The Wealth of Nations with his famous pin factory example. One man draws out the wire, another straights it, a third cuts it, a fourth points it, a fifth grinds it at the top for receiving the head. To make the head requires two or three distinct operations. To put it on is a peculiar business. To whiten the pins is another. It is even a trade by itself to put them into the paper. And the important business of making a pin is in this manner divided into about 18 distinct operations, which in some manufactories are all performed by distinct hands, though in others the same man will sometimes perform two or three of them. By dividing their labour, ten workers could make upwards of 48,000 pins in a day, while if they were working in isolation each worker would scarce be able to make one. Does all this sound excessively materialistic? Well, humankind's physiological needs are a fact of life. You can't buy true love, but neither can you love when you're dead from hypothermia. And it's difficult to contemplate the universe, the soul, or a work of high art when you're delirious from hunger. In other words, we cannot ascend toward the top of Maslow's pyramid without first climbing its bottom level. Thanks to the wealth made possible by unlocking the efficiencies of the division of labour, the civilians of civilisation can afford to provide for less urgent wants, like spiritual, intellectual and aesthetic desires. If a community grows wealthy enough, even the provision of these higher ends can be enhanced by specialisation and the division of labour. As Will the Rant wrote in the first volume of The Story of Civilisation, in the city some men are set aside from the making of material things and produce science and philosophy, literature and art. And, since there's nothing wrong with wanting to enjoy life, it's also worth noting that the efficiency of the division of labour is what affords citizens the comforts, conveniences, amenities and luxuries associated with city life. Mises ascribed so much significance to the law of comparative advantage that he renamed it the Law of Association. He deemed the division of labour to be the very basis of human society. Humans are capable of recognising the benefit of dividing their labour with others and so they do so. This creates economic interdependence. The builder and weaver depend on the farmer for their food, the farmer and weaver depend on the builder for their shelter and the farmer and builder depend on the weaver for their clothes. This interdependence dramatically increases the costs of conflict and the desirability of peaceful coexistence. The builder might have the strength to murder the farmer and steal his crop, but then he'll have to grow his own food henceforth, which again is far less efficient than selling houses and using the proceeds to buy food. So the division of labour breeds civility, which is another characteristic mark of civilisation, norms that minimise conflict, ranging from human rights, life, liberty and property, to manners. And this civility in turn fosters still further economic cooperation. Now we have a picture of civilisation, the division of labour, prosperity and civility. And this image is most vividly portrayed by an ideal thriving city bustling with industry, commerce, intellectual pursuits, lively discourse, artistic creation and urban delights. But to realise this picture, commerce and the division of labour within the city are not enough. As Plato wrote, to find a place where nothing need be imported is well nigh impossible. The law of comparative advantage doesn't stop operating at city limits nor even at water's edge. Foreigners too have comparative advantages different from us, not only in aptitudes but also in access to natural resources. So not only does it make sense to have commerce with our neighbours but with distant peoples. Why grow bananas in Massachusetts hot houses when you can catch lobsters and sell them for enough money to buy more bananas from balmy Latin America than you could have possibly grown in frigid New England. By facilitating such cross-border commerce, merchants extend the division of labour across the whole world, vastly increasing human productivity and living standards. Just as it does within the city, the international division of labour creates international economic interdependence, which fosters international peace. If goods cross borders, armies are less likely to. It makes little sense to bomb your foreign markets or your supply chain. Trade is cosmopolitan, cosmopolis being Greek for world city, in the sense that it extends the civilisation of the city, the division of labour, prosperity and civility across the whole world. International commerce is also cosmopolitan, in the sense that it brings together people of different cultures for mutual economic gain, stimulates cross-cultural learning and understanding and increases the costs of prejudice. As Voltaire wrote in the 18th century, go into the London Stock Exchange and you will see representatives of all nations gathered there for the service of mankind. There the Jew, Mohammedan and the Christian deal with each other as if they were of the same religion and give the name of Infidel only to those who go bankrupt. Again the division of labour promotes civility. Now that we are more familiar with the meaning of civilisation, we are finally in a position to judge the pro-Trump right and the anti-Trump left, both of whom posture as protectors of civilisation. Protectionism, the doctrine favoured by Trump and his fans, disintegrates the global division of labour. It bars producers on both sides of the trade barrier from focusing fully on their greatest comparative advantage and so makes them far less efficient and consumers in both countries poorer. Every protectionist measure is a step back toward the deprivation of primitive autarchy. It is also a step on the road to war. Just as the division of labour breeds civility, economic nationalism leads back to the savagery of tribal warfare, now with larger tribes called nations. If goods don't cross borders, armies more likely will. Even more dangerous to world civilisation than the barbarians at the gates are the barbarians with the gates, barriers to international commerce. Trump is also guilty of domestically divisive policies and rhetoric. However, many of his critics are quite hypocritical to chant he will not divide us. The left is obsessed with class warfare and identity politics. Far from healing divisions in society, these preoccupations only create and exacerbate them, threatening the civil harmony generated by the division of labour. Class warfare disintegrates the natural harmony of interests among producers and consumers, sellers and buyers, hires and higheres, capitalists and labourers, the wealthy and the non-wealthy, etc., by pitting these groups against each other. It also impoverishes all by hampering the domestic division of labour. As discussed above, commerce breaks down prejudice and fosters cosmopolitan civility, not only among cultures and religions, but between sexes and among races. Social justice warriors threaten to undo this genuine progress by sowing civil strife with their hair-trigger sensitivities, witch hunts against thought criminals, and predilection for manufacturing identity-based grievances and victim complexes. Far from effectively dissuading bigotry, such excesses seem to be driving people to join the alt-right in disgust and out of defiance. As both Antifa and the alt-right escalate their rhetoric and rowdiness, even to the point of periodically brawling in the streets like red shirts and brown shirts in the late Weimar Republic, it's good to keep in mind that neither are friends of civilisation and neither are worth siding with.