"… is from the abstract of Solomon Polachek’s and Carlos Seiglie’s important 2006 paper, “Trade, Peace and Democracy: An Analysis of Dyadic Dispute“:A slice from the rest of Prof. Boudreaux's post, which is well worth reading in it's entirety [emphasis added]:At least since 1750 when Baron de Montesquieu declared peace is the natural effect of trade, a number of economists and political scientists espoused the notion that trade among nations leads to peace…. The greater two nations’ gain from trade the more costly is bilateral (dyadic) conflict. This notion forms the basis of Baron de Montesquieu’s assertion regarding dyadic dispute. This paper develops an analytical framework showing that higher gains from trade between two trading partners (dyads) lowers the level of conflict between them…. Crosssectional evidence using various data on political interactions confirms that trading nations cooperate more and fight less. A doubling of trade leads to a 20% diminution of belligerence."
"When people trade they must engage with others, mostly strangers; when people trade across political borders they must engage with greater numbers of strangers still. This trade, though, makes the strangers less strange to each other, because each learns better what the other is like and what the other likes and dislikes. Trade is peaceful, and so it reveals to each trader the other’s humanity; war reveals the other’s brutality. Each party to every trade gains; with war, one party certainly losses, and even the ‘winner’ might well, in the end, have lost so much to have made the entire activity a losing proposition."
and to file under sentences I wish I'd written:
"The retaliation incited by war is negative-sum and stupid: “You killed someone whose passport is issued by the same agency as that issues my passport, so I’ll kill someone whose passport is issued by the same agency that issues your passport. That’ll teach you!”"