More borders, cheaper conflict steadily increase number of wars

fire a shot?” “No” is the answer to both these questions. If one removes “America’s wars” altogether from the data, it makes no difference: the rising trend is still there. Other scholars have shown that the average distance between countries at war has fallen steadily since the 1950s.

Looking specifically at the countries that have initiated disputes, the researchers show, larger countries (defined by GDP) have tended to make more frequent military interventions, but there has been no increase in this tendency over the 130 years of their study. They also show there is no tendency for richer countries (defined by GDP per head) to make war more often than others, and again this has not changed over 130 years. In other words, the readiness to embark on military adventures is scattered fairly uniformly across the global income distribution.

This raises two sorts of problems. One is that it is somewhat alarming. The other is that it is a bit of a puzzle. Much of what we know, or think we know, says this should not be happening. The countries of the world have tended to become richer, more democratic, and more interdependent. The thinkers of the Enlightenment held that these things ought generally to make the world more peaceful. Much political science is built on the idea that the political leaders of richer, more democratic countries have fewer incentives to make war and are more constrained from doing so.

Professor Mark Harrison said: “We do not think these ideas are wrong, but they are incomplete. Without being certain of the answer, we think political scientists have focused too much on preferences for war (the “demand side”) and not enough on capabilities (the “supply side”). Capabilities may be the missing factor in the story of the rising frequency of wars. We argue that the same factors that should have depressed the incentives for rulers to choose conflict are also increasing the capacity for war. In other words, we are making war more frequently, not because we want to, but because we can.”

The release notes that the research gives three explanations for this. Firstly, economic growth has made destructive power cheaper, not just absolutely cheaper but cheaper relative to civilian goods. Second, the key to modern states’ acquisition of destructive power was the ability to tax and borrow more than ever before, and the growth of fiscal capacity was hugely assisted by the rise of democracy. Third, war is disruptive of trade, but those countries that succeeded in maintaining external trading links in wartime could wage war more effectively.

Professor Mark Harrison concluded: “In other words, the very things that should make politicians less likely to want war – productivity growth, democracy, and trading opportunities – have also made war cheaper. We have more wars, not because we want them, but because we can. Finally, under present international arrangements this deep seated tendency is not something that any one country is going to be able to control.”

— Read more in Mark Harrison and Nikolaus Wolf, “The frequency of wars,” forthcoming in the Economic History Review.