The capacity to create imagined communities is humanity’s strength and among its biggest weaknesses. Imagined community defines what people share. But what binds them together divides them from others. Today, as in the past, leaders foment aggrieved nationalism to justify despotism and even war.
For much of human history, war was seen as the natural relationship between societies. Victory brought plunder, power and prestige, at least for elites. Mobilising resources for war was a core role of states. Justifying such mobilisation was a core role of culture.
Another way exists to achieve prosperity: commerce. The balance between commerce and plunder is complex. Both require strong institutions supported by effective cultures. But war requires armies, underpinned by loyalty, while commerce requires security, underpinned by justice.
Perhaps the greatest contribution of economics is the idea that societies will gain more from seeking to trade with one another than trying to conquer one another. Moreover, the richer their partners, the greater the opportunities for mutually enriching commerce. The wise relationship between states, therefore, is one of co-operation, not war, and trade, not isolation. This brilliant idea happens to be correct. But it is also counter-intuitive, even disturbing. It means that one might gain more from foreigners than fellow citizens. It erodes a sense of belonging to the imagined tribe. For many, this erosion of tribal loyalty is threatening. It becomes more threatening if foreigners are allowed to immigrate freely. Who, people ask, are these strangers, who reside in our home and share in its benefits?