Oop! I'm doing another extended quote.

From Bryan Caplan's The 4 Boneheaded Biases of Stupid Voters
(And we're all stupid voters.) in Reason Magazine.

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.”

Yeah, yeah, you can't outsource Defense, but look back at that first paragraph and you'll guess what I say about that.