We would all like to think that the world is progressing towards being a better place.
As well as the alleviation of poverty and improvement of public health, the widespread extension of opportunity and creation of life chances, improvements in and spreading out of wealth, we would all like to think that war within and between countries is becoming rarer. Such an enormous investment has been made in trans-national institutions variously aimed at fostering peaceful co-existence and punishing war crimes that is the fruit of a longing for peace to become the norm.
Swords into ploughshares, perhaps. But is it the case in practice?
One obvious answer at the micro level is that it depends on where you live. I count myself fortunate to have been born and brought up in the United Kingdom during a period in which it has been at war (e.g. Falklands, Gulf and Iraq wars plus extended involvement in Afghanistan) and also an internal conflict akin to a civil war, but nothing that touched me directly. That said, my brother-in-law took a bus from a West London stop in 2001 that less than an hour later was destroyed in a bomb blast associated with Irish Nationalist actions.
But this experience is in total contrast during my lifetime to dwellers in at least parts of Sri Lanka, Nigeria, Sudan, former Yugoslavia, Yemen, Indonesia, Crimea, Algeria to name but a few conflict zones. Most of these would be categorised as civil wars rather than inter-state conflicts, I guess, although for those caught up in it the difference might be somewhat moot.
An alternative answer might be found in aggregate macro analysis of overall trends in the incidence and impact of wars. In interest in this is why my eye was drawn to a recent reference to a study of 2017 by Aaron Clauset under the aegis of OEF Research that used statistical modelling to assess whether the world was over time seeing fewer inter-state wars. The report seems to be freely available at https://oefresearch.org/sites/default/files/documents/publications/enduring_threat_interstate_wars.pdf.
The study is well worth a read on several levels. It addresses questions affecting data collection, accuracy and risks of bias in the underlying data set, measurement and methodological issues and other factors including the average size and number of states, including categorisation impacts between the intra- and inter-state distinction. It also uses several types of analysis to assess consistency under different approaches.
So, what is the answer? There is no point in my attempting to summarise the report in full but, recognising the risk of over-simplification, several things of interest can be drawn from it overall.
(1) The periods 1823 to 1914 and 1940 onwards (1940 because the methodology uses the onset of war as its basis, not eventual conclusion) are not statistically different to each other, whereas the period in between, 1914 to 1940, is to put it mildly, over-endowed with interstate conflict.
(2) The subsequent “Long Peace” has so far largely served to balance out that particularly bloody intervening period.
(3) Whilst the recent trend is encouraging, to reach statistical certainty that there has truly been a shift away from interstate conflict compared to the pre-World War I period we would have to see the current pattern continue or improve further for a period of between 100 and 150 years.
(4) There is no room for complacency and the risk of interstate war remains high.
On that last point, I am choosing to reproduce the closing paragraph of the report in full, but commend you to read this fascinating, rigorous piece of work in full.
"If the […] hypothesis is correct, however, over this same period of time [the next 100 to 150 years] the risk of another war with tens of millions of battle deaths is shockingly high (to say nothing of the longer run likelihood of a civilization-ending conflict). These facts and insights serve to illustrate the fundamental importance of concerted and serious work to ensure that the Long Peace endures and to prevent fragile peace-promoting institutions or systems from falling in the face of stable or contingent processes that drive the production of war. Much of this work must be done on the policy side. In the long run, however, research will play a crucial role by developing and evaluating mechanistic explanations, at multiple scales, of the likelihood of war, which will help shed new light on what policies—at what scales—will promote peace.”