The quote of the day is from Charles Darwin’s 1871 book The Descent of Man, and Selection in Relation to Sex:

As man advances in civilization, and small tribes are united into larger communities, the simplest reason would tell each individual that he ought to extend his social instincts and sympathies to all members of the same nation, though personally unknown to him. This point being once reached, there is only an artificial barrier to prevent his sympathies extending to the men of all nations and races.

That “artificial barrier” is composed largely of the poison of nationalism — nationalism that causes each of its victims mindlessly to believe that a harm done to an innocent stranger in another nation is, if indeed an evil at all, a lesser evil than is the same harm done to an innocent stranger in his or her own nation — nationalism that generates the idiotic misconception that trade that is confined within the borders of one nation differs in essential ways from trade that crosses the borders of nations — nationalism that so distorts people’s thought processes that they whoop joyfully and cheer loudly when a bloviating ignoramus such as Donald Trump, or a frightfully uninformed dirigiste such as Bernie Sanders, threatens to cage or shoot them if they insist on improving their lives by trading peacefully with people of other nations.

Cross-posted from Cafe Hayek.