“It is nearly a general rule that wherever there are gentle mores (des moeurs douces) there is commerce; and that wherever there is commerce there are gentle mores.” So wrote Montesquieu in De l’Esprit des Lois (1748).
This rule, he believed, applied to relations between individuals, and also between countries: “The natural effect of commerce is to lead to peace. Two nations that trade with each other make themselves reciprocally dependent.” Commercial interests, he predicted, will tame nations’ passions.
This thesis — that trade breeds peace — became known as the doux commerce thesis. Other great minds endorsed it. According to Thomas Paine, for example, “if commerce were permitted to act to the universal extent it is capable, it would extirpate the system of war” (The Rights of Man, 1791).
Immanuel Kant agreed: it is thanks to trade that “nations first entered into peaceful relations with one another, and thus achieved mutual understanding, community of interests, and peaceful relations, even with the most distant of their fellows” (Zum ewigen Frieden, 1795).
Many years and many wars later, the thesis was a major source of inspiration for the process of European unification. “World peace cannot be safeguarded without the making of creative efforts proportionate to the dangers which threaten it”, says the very first sentence of Robert Schuman’s pioneering declaration of 9 May 1950. And what form will these creative efforts take? The organisation to be created “will ensure the fusion of markets and the expansion of production.”
This fusion of markets seems to have done the job expected from it. On 10 December 2012, the European Union was awarded the Nobel Peace prize on the ground that it showed that "by building up mutual confidence, historical enemies can become close partners".
On receiving the prize, European Commission president José Manuel Barroso described the European Union as “a successful example of peaceful reconciliation based on economic integration”, while European Council president Herman Van Rompuy highlighted the Union’s “secret weapon”: “an unrivalled way of binding our interests so tightly that war becomes materially impossible”.
But then came the war in Ukraine. The deepening economic interdependence between Russia and the West did not prevent it. Nor did the Wandel durch Handel strategy (“Change through trade”) consistently deployed with Russia by Europe’s largest economy. Does this mean that the doux commerce thesis should be dumped? Perhaps not.
To start with, all that the first sentence by Montesquieu quoted above asserts is a correlation between commerce and peace, not a causal link between the former and the latter. Gentle mores could be a condition for the flourishing of trade rather than one of its effects.
The abrupt reduction in trade with Russia that resulted from the war would then provide a straightforward confirmation of Montesquieu’s thesis of the existence of a correlation. Alas, this would be too easy. The second quote makes clear that, at least where international relations were concerned, Montesquieu believed in the pacifying effect of commerce, and this is how the thesis is commonly understood.
However, a pacifying effect need not mean making war impossible. It could also mean, more modestly, making it less probable or less total. This opens the door to a second way of reconciling the doux commerce thesis with the uncomfortable fact of the Ukrainian war. Is it not quite obvious that the self-restraint shown by several European countries, not least Germany, in their military support for Ukraine has something to do with their dependence on imports from Russia? Is it similarly not quite obvious that China would have embraced this opportunity to hit the West by resolutely siding with Russia, had it not been for its heavy dependence from the West for both imports and exports? Commercial interdependence did not manage to maintain peace, but it made the military conflict less total — so far — than it would otherwise have been.
There is yet a third and more instructive way of rescuing the thesis. Rather than weakening it by retreating from a causal claim to a sheer correlation, or from making war impossible to making it less harsh, one can try to specify the conditions under which it holds. To get a first idea of the conditions under which it does not hold, just ask yourself the following question. What is it that persuaded Putin that he could afford to break the peace despite the high level of mutual commercial dependence? Arguably the fact that he believed that Russia could cope for longer with the disruption of trade relations than could its European neighbours.
He had two good reasons to believe this. Firstly, dependence on oil and gas makes itself felt more quickly than does dependence on most manufactured goods and services. Secondly, the shortages resulting from the interruption of trade by war weigh more heavily on decision-making in democratic than in autocratic regimes: governments have to take account of the impatience of an electorate less susceptible to manipulation by war propaganda.
If this analysis is correct, it can remain true that commercial interdependence breeds peace, but only in the absence of temporal asymmetries of the sort mentioned above. As this condition is not satisfied at the global level, blind globalization is not a secure recipe for peace. It is not only fossil fuels and other essential raw materials that are strongly concentrated in one or a few countries and can therefore give rise to dangerous asymmetries, but also, owing to massive economies of scale, the production of manufactured goods in constant urgent demand, such as electronic chips.
The verdict is different for Europe. Whether there would have been yet another war between France and Germany in the absence of European economic integration will never be known for certain. But the fact that a war between EU member states has become unimaginable has certainly something to do with European integration. What does the trick is in part, consistently with Montesquieu’s doctrine, the commercial interdependence that further developed as a result of member states exploiting comparative advantage and economies of scale in a shared market.
But it is no less the stabilization of liberal democracy throughout the Union. And it is probably above all the laborious shaping of the political institutions required to tame the shared market, prevent it from ransacking member states’ social protection systems and develop EU-wide solidarity.
None of this would have happened without the high level of commercial interdependence brought about by European economic integration. But commercial interdependence alone would not have produced the secure intra-EU peace we have long been enjoying.
