I must admit that I am somewhat depressed by the state of the world today. Deflationary monetary policies in Europe, increased protectionist tendencies and war and geopolitical tensions around the world. It is no secret that I think it is all connected.

But why do voters around the world rally behind the cries for closed borders and even more military build-ups? Why do policy makers – democratic and non-democratic – find it in their interest to stir up anti-immigrant sentiment, geopolitical tensions and to introduce protectionist measures?

Bryan Caplan might provide the answer – the “anti-foreign bias” of rationally irrational voters – this is from a piece Bryan wrote for Reason from 2007: 

A shrewd businessman I know has long thought that everything wrong in the American economy could be solved with two expedients: 1) a naval blockade of Japan, and 2) a Berlin Wall at the Mexican border.

Like most noneconomists, he suffers from anti-foreign bias, a tendency to underestimate the economic benefits of interaction with foreigners. Popular metaphors equate international trade with racing and warfare, so you might say that anti-foreign views are embedded in our language. Perhaps foreigners are sneakier, craftier, or greedier. Whatever the reason, they supposedly have a special power to exploit us.

There is probably no other popular opinion that economists have found so enduringly objectionable. In The Wealth of Nations, Adam Smith admonishes his countrymen: “What is prudence in the conduct of every private family, can scarce be folly in a great kingdom. If a foreign country can supply us with a commodity cheaper than we ourselves can make it, better buy it of them with some part of the produce of our own industry.”

As far as his peers were concerned, Smith’s arguments won the day. More than a century later, Simon Newcomb could securely observe in the Quarterly Journal of Economics that “one of the most marked points of antagonism between the ideas of the economists since Adam Smith and those which governed the commercial policy of nations before his time is found in the case of foreign trade.” There was a little backsliding during the Great Depression, but economists’ pro-foreign views abide to this day.

Even theorists, such as Paul Krugman, who specialize in exceptions to the optimality of free trade frequently downplay their findings as abstract curiosities. As Krugman wrote in his 1996 book Pop Internationalism: “This innovative stuff is not a priority for today’s undergraduates. In the last decade of the 20th century, the essential things to teach students are still the insights of Hume and Ricardo. That is, we need to teach them that trade deficits are self-correcting and that the benefits of trade do not depend on a country having an absolute advantage over its rivals.”

Economics textbooks teach that total output increases if producers specialize and trade. On an individual level, who could deny it? Imagine how much time it would take to grow your own food, while a few hours’ wages spent at the grocery store can feed you for weeks. Analogies between individual and social behavior are at times misleading, but this is not one of those times. International trade is, as the economic writer Steven Landsburg explains in his 1993 book The Armchair Economist, a technology: “There are two technologies for producing automobiles in America. One is to manufacture them in Detroit, and the other is to grow them in Iowa. Everybody knows about the first technology; let me tell you about the second. First you plant seeds, which are the raw materials from which automobiles are constructed. You wait a few months until wheat appears. Then you harvest the wheat, load it onto ships, and sail the ships westward into the Pacific Ocean. After a few months, the ships reappear with Toyotas on them.”

How can anyone overlook trade’s remarkable benefits? Adam Smith, along with many 18th- and 19th-century economists, identifies the root error as misidentification of money and wealth: “A rich country, in the same manner as a rich man, is supposed to be a country abounding in money; and to heap up gold and silver in any country is supposed to be the best way to enrich it.” It follows that trade is zero sum, since the only way for a country to make its balance more favorable is to make another country’s balance less favorable.

Even in Smith’s day, however, his story was probably too clever by half. The root error behind 18th-century mercantilism was an unreasonable distrust of foreigners. Otherwise, why would people focus on money draining out of “the nation” but not “the region,” “the city,” “the village,” or “the family”? Anyone who consistently equated money with wealth would fear all outflows of precious metals. In practice, human beings then and now commit the balance of trade fallacy only when other countries enter the picture. No one loses sleep about the trade balance between California and Nevada, or me and iTunes. The fallacy is not treating all purchases as a cost but treating foreign purchases as a cost.

Anti-foreign bias is easier to spot nowadays. To take one prominent example, immigration is far more of an issue now than it was in Smith’s time. Economists are predictably quick to see the benefits of immigration. Trade in labor is roughly the same as trade in goods. Specialization and exchange raise output—for instance, by letting skilled American moms return to work by hiring Mexican nannies.

In terms of the balance of payments, immigration is a nonissue. If an immigrant moves from Mexico City to New York and spends all his earnings in his new homeland, the balance of trade does not change. Yet the public still looks on immigration as a bald misfortune: jobs lost, wages reduced, public services consumed. Many in the general public see immigration as a distinct danger, independent of, and more frightening than, an unfavorable balance of trade. People feel all the more vulnerable when they reflect that these foreigners are not just selling us their products. They live among us.

It is misleading to think of “foreignness” as a simple either/or. From the viewpoint of the typical American, Canadians are less foreign than the British, who are in turn less foreign than the Japanese. From 1983 to 1987, 28 percent of Americans in the National Opinion Research Center’s General Social Survey admitted they disliked Japan, but only 8 percent disliked England, and a scant 3 percent disliked Canada.

Objective measures like the volume of trade or the trade deficit are often secondary to physical, linguistic, and cultural similarity. Trade with Canada or Great Britain generates only mild alarm compared to trade with Mexico or Japan. U.S. imports from and trade deficits with Canada exceeded those with Mexico every year from 1985 to 2004. During the anti-Japan hysteria of the 1980s, British foreign direct investment in the U.S. always exceeded that of the Japanese by at least 50 percent. Foreigners who look like us and speak English are hardly foreign at all.

Calm reflection on the international economy reveals much to be thankful for and little to fear. On this point, economists past and present agree. But an important proviso lurks beneath the surface. Yes, there is little to fear about the international economy itself. But modern researchers rarely mention that attitudes about the international economy are another story. Paul Krugman hits the nail on the head: “The conflict among nations that so many policy intellectuals imagine prevails is an illusion; but it is an illusion that can destroy the reality of mutual gains from trade.” We can see this today most vividly in the absurdly overblown political reactions to the immigration issue, from walls to forcing illegal workers currently in America to leave before they can begin an onerous procedure to gain paper legality.