How Likely Is (Nuclear) War Between the United States and Russia?

Last week, Vox ran a long piece by Max Fisher claiming that “the prospect of a major war, even a nuclear war, in Europe has become thinkable, [experts] warn, even plausible.” Without ever clarifying what “thinkable” or “plausible” mean in this context, Fisher seems to be arguing that, while still unlikely, the probability of a nuclear war between the United States and Russia is no longer small and is rising.

I finished Fisher’s piece and wondered: Is that true? As someone who’s worked on a couple of projects (here and here) that use “wisdom of crowds” methods to make educated guesses about how likely various geopolitical events are, I know that one way to try to answer that question is to ask a bunch of informed people for their best estimates and then average them.

So, on Thursday morning, I went to SurveyMonkey and set up a two-question survey that asks respondents to assess the likelihood of war between the United States and Russia before 2020 and, if war were to happen, the likelihood that one or both sides would use nuclear weapons. To elicit responses, I tweeted the link once and posted it to the Conflict Research Group on Facebook and the IRstudies subreddit. The survey is still running [UPDATE: It’s now closed, because Survey Monkey won’t show me more than the first 100 responses without a paid subscription], but 100 people have taken it so far, and here are the results—first, on the risk of war:

wwiii.warrisk

And then on the risk that one or both sides would nuclear weapons, conditional on the occurrence of war:

wwiii.nukerisk

These results come from a convenience sample, so we shouldn’t put too much stock in them. Still, my confidence in their reliability got a boost when I learned yesterday that a recent survey of international-relations experts around the world asked an almost-identical question about the risk of a war and obtained similar results. In its 2014 survey, the TRIP project asked: “How likely is war between the United States and Russia over the next decade? Please use the 0–10 scale with 10 indicating that war will definitely occur.” They got 2,040 valid responses to that question, and here’s how they were distributed:

trip.warrisk

Those results are centered a little further to the right than the ones from my survey, but TRIP asked about a longer time period (“next decade” vs. “before 2020”), and those additional five years could explain the difference. It’s also important to note that the scales aren’t directly comparable; where the TRIP survey’s bins implicitly lie on a linear scale, mine were labeled to give respondents more options toward the extremes (e.g., “Certainly not” and “Almost certainly not”).

In light of that corroborating evidence, let’s assume for the moment that the responses to my survey are not junk. So then, how likely is a US/Russia war in the next several years, and how likely is it that such a war would go nuclear if it happened? To get to estimated probabilities of those events, I did two things:

  1. Assuming that the likelihoods implicit my survey’s labels follow a logistic curve, I converted them to predicted probabilities as follows: p(war) = exp(response – 5)/(1 + exp(response – 5)). That rule produces the following sequence for the 0–10 bins: 0.007, 0.018, 0.047, 0.119, 0.269, 0.500, 0.731, 0.881, 0.953, 0.982, 0.993.

  2. I calculated the unweighted average of those predicted probabilities.

Here are the estimates that process produced, rounded up to the nearest whole percentage point:

  • Probability of war: 11%
  • Probability that one or both sides will use nuclear weapons, conditional on war: 18%

To translate those figures into a single number representing the crowd’s estimate of the probability of nuclear war between the US and Russia before 2020, we take their product: 2%.

Is that number different from what Max Fisher had in mind when he wrote that a nuclear war between the US and Russia is now “thinkable,” “plausible,” and “more likely than you think”? I don’t know. To me, “thinkable” and “plausible” seem about as specific as “possible,” a descriptor that applies to almost any geopolitical event you can imagine. I think Max’s chief concern in writing that piece was to draw attention to a risk that he believes to be dangerously under-appreciated, but it would be nice if he had asked his sources to be more specific about just how likely they think this calamity is.

More important, is that estimate “true”? As Ralph Atkins argued in a recent Financial Times piece about estimating the odds of Grexit, it’s impossible to say. For unprecedented and at least partially unique events like these—an exit from the euro zone, or a nuclear war between major powers—we can never know the event-generating process well enough to estimate their probabilities with high confidence. What we get instead are summaries of peoples’ current beliefs about those events’ likelihood. That’s highly imperfect, but it’s still informative in its own way.

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Whither Organized Violence?

The Human Security Research Group has just published the latest in its series of now-annual reports on “trends in organized violence around the world,” and it’s essential reading for anyone deeply interested in armed conflict and other forms of political violence. You can find the PDF here.

The 2013 edition takes Steven Pinker’s Better Angels as its muse and largely concurs with Pinker’s conclusions. I’ll sheepishly admit that I haven’t read Pinker’s book (yet), so I’m not going to engage directly in that debate. Instead, I’ll call attention to what the report’s authors infer from their research about future trends in political violence. Here’s how that bit starts, on p. 18:

The most encouraging data from the modern era come from the post–World War II years. This period includes the dramatic decline in the number and deadliness of international wars since the end of World War II and the reversal of the decades-long increase in civil war numbers that followed the end of the Cold War in the early 1990s.

What are the chances that these positive changes will be sustained? No one really knows. There are too many future unknowns to make predictions with any degree of confidence.

On that point, political scientist Bear Braumoeller would agree. In an interview last year for Popular Science (here), Kelsey Atherton asked Braumoeller about Braumoeller’s assertion in a recent paper (here) that it will take 150 years to know if the downward trend in warfare that Pinker and others have identified is holding. Braumoeller replied:

Some of this literature points to “the long peace” of post-World War II. Obviously we haven’t stopped fighting wars entirely, so what they’re referring to is the absence of really really big wars like World War I and World War II. Those wars would have to be absent for like 70 to 75 more years for us to have confidence that there’s been a change in the baseline rate of really really big wars.

That’s sort of a separate question from how we know whether there are trends in warfare in general. We need to understand that war and peace are both stochastic processes. We need a big enough sample to rule out the historical average, which is about one or two big wars per century. We just haven’t had enough time since World War I and World War II to rule out the possibility that nothing’s changed.

I suspect that the authors of the Human Security Report would not dispute that claim, but after carefully reviewing Pinker’s and their own evidence, they do see causes for cautious optimism. Here I’ll quote at length, because I think it’s important to see the full array of forces taken into consideration to increase our confidence in the validity of the authors’ cautious speculations.

The case for pessimism about the global security future is well rehearsed and has considerable support within the research community. Major sources of concern include the possibility of outbreaks of nuclear terrorism, a massive transnational upsurge of lethal Islamist radicalism, or wars triggered by mass droughts and population movements driven by climate change.

Pinker notes reasons for concern about each of these potential future threats but also skepticism about the more extreme claims of the conflict pessimists. Other possible drivers of global violence include the political crises that could follow the collapse of the international financial system and destabilizing shifts in the global balance of economic and military power—the latter being a major concern of realist scholars worried about the economic and military rise of China.

But focusing exclusively on factors and processes that may increase the risks of large-scale violence around the world, while ignoring those that decrease it, also almost certainly leads to unduly pessimistic conclusions.

In the current era, factors and processes that reduce the risks of violence not only include the enduring impact of the long-term trends identified in Better Angels but also the disappearance of two major drivers of warfare in the post–World War II period—colonialism and the Cold War. Other post–World War II changes that have reduced the risks of war include the entrenchment of the global norm against interstate warfare except in self-defence or with the authority of the UN Security Council; the intensification of economic and financial interdependence that increases the costs and decreases the benefits of cross-border warfare; the spread of stable democracies; and the caution-inducing impact of nuclear weapons on relations between the major powers.

With respect to civil wars, the emergent and still-growing system of global security governance discussed in Chapter 1 has clearly helped reduce the number of intrastate conflicts since the end of the Cold War. And, at what might be called the “structural” level, we have witnessed steady increases in national incomes across the developing world. This is important because one of the strongest findings from econometric research on the causes of war is that the risk of civil wars declines as national incomes—and hence governance and other capacities—increase. Chapter 1 reports on a remarkable recent statistical study by the Peace Research Institute, Oslo (PRIO) that found that if current trends in key structural variables are sustained, the proportion of the world’s countries afflicted by civil wars will halve by 2050.

Such an outcome is far from certain, of course, and for reasons that have yet to be imagined, as well as those canvassed by the conflict pessimists. But, thanks in substantial part to Steven Pinker’s extraordinary research, there are now compelling reasons for believing that the historical decline in violence is both real and remarkably large—and also that the future may well be less violent than the past.

After reading the new Human Security Report, I remain a short-term pessimist and long-term optimist. As I’ve said in a few recent posts (see especially this one), I think we’re currently in the thick of period of systemic instability that will continue to produce mass protests, state collapse, mass killing, and other forms of political instability at higher rates than we’ve seen since the early 1990s for at least the next year or two.

At the same time, I don’t think this local upswing marks a deeper reversal of the long-term trend that Pinker identifies, and that the Human Security Report confirms. Instead, I believe that the global political economy is continuing to evolve in a direction that makes political violence less common and less lethal. This system creep is evident not only in the aforementioned trends in armed violence, but also in concurrent and presumably interconnected trends in democratization, socio-economic development, and global governance. Until we see significant and sustained reversals in most or all of these trends, I will remain optimistic about the directionality of the underlying processes of which these data can give us only glimpses.

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