Category Archives: nuclear weapons

Why Are Nuclear Agreements Credible?

Compliance is a central issue in arms control negotiations. Take Iran as an example. The United States has long pitched a better world standing for Iran in exchange for Tehran ending its pursuit of nuclear weapons. President Obama once described such an agreement in the following way:

Iran must comply with UN Security Council resolutions and make clear it is willing to meet its responsibilities as a member of the community of nations. We have offered IRan a clear path toward greater international integration if it lives up to its obligations…. But the Iranian government must now demonstrate through deeds its peaceful intentions…

At first pass, such a trade may seem impossible. The United States has to give concessions to Iran to make nonproliferation look attractive. But nothing stops Iran from accepting those concessions, building nuclear weapons anyway, and then leveraging its atomic threat for all of the corresponding benefits. Worse, if the United States expects this, then it has no incentive to offer any sort of deal in the first place.

I, for one, certainly felt that way when I watched Obama pitched the deal in 2009. In fact, I wrote a book that explores those incentives, which just came out:

Bargaining over the Bomb’s central finding is that, despite appearances to the contrary, those deals work. Countries like Iran do not have an inherent incentive to take those concessions and run with them. This is true even if Iran could build nuclear weapons without the United States noticing until the bombs are finished.

A little bit of formalization helps explain why. All we need are a few parameters to map out the incentives. Suppose that nuclear weapons are useful for coercive leverage, and let p be the percentage of the benefits the would-be proliferator can extract once it has acquired those weapons. Let c > 0 represent the cost of building them. Finally, let 𝛿 > 0 represent how much the would-be proliferator cares about the future.

From this, we can calculate what portion of the benefits the would-be proliferator requires now and for the rest of time to not want to develop nuclear weapons. Let x be that necessary share, so that if a deal is made and sustained, the would-be proliferator receives x for today and 𝛿x for the future, for a total payoff of (1 + 𝛿)x.

The apparent barrier to agreements is that the would-be proliferator can take x for today, pay the cost c, acquire nuclear weapons, and then capture p portion of the benefits in the future. And if it can get away with keeping that x value in the interim, why wouldn’t it?

Well, summing up that payoff for proliferation and comparing it to the payoff for accepting the deal, the potential proliferator prefers to not build if:

(1 + 𝛿)x > x + 𝛿p – k
x > p – k/𝛿

In fact, the would-be proliferator is willing to accept an agreement after all!

Where did intuition fail us? The key to understanding why an agreement works is that proliferation only provides a finite amount of benefits. If the opponent offers the potential proliferator those benefits up front, then proliferating at that point is unprofitable—developing weapons leaves the potential proliferator exactly where it was before, but it must pay the costs of proliferation in the interim.

We can see those incentives in the minimum acceptable offer. The value x must be close to p—in other words, the quantity of concessions given immediately must be close to the benefits the potential proliferator would receive if it built the weapons.

To be more precise, the opposing state can fudge this a little—by k/𝛿, to be exact. This is because, by accepting the deal, the would-be proliferator does not have to pay the cost to build. Note that when the would-be proliferator does not care at all about the future, 𝛿 goes toward 0, and thus the potential proliferator needs less to accept an agreement.

In Bargaining over the Bomb, I develop this model in much greater depth, providing context in how the states calculate the benefits of proliferation, how preventive war fits into this, and whether the opponent would actually want to offer such a deal. But the central finding remains: would-be proliferators are happy to accept agreements. The first half of the book explores some facets of those agreements while the second half explains why bargaining may still fail.

Building this model and writing the book has made me a lot more optimistic about whether negotiations with countries like Iran can succeed. If you share the same skepticism I once did, I would encourage you to read the book and think more about the central incentives at play. I don’t think agreements are universally workable, but they should be a critical part of our policymakers’ tool kits.

How Long Does It Take to Publish an Academic Book?

My first book with original research just came out. (Amazon even has proof!) This excites me, as you can see from this picture from a couple of weeks ago, when I held it it my hands for the first time:

Part of my elation came from reflecting on just how long I had been working on the project. I thought it might be interesting for younger scholars to get a full perspective, so I am writing out a brief timeline of book-related events here. It might also give a better overview on the origins, thought process, and evolution of a long-form project. There is also going to be a healthy dose of luck. And regardless of utility to others, it’s going to be cathartic for me.

Here goes:

9/25/2009: Yes, we are starting almost ten years ago. I was in my gap year between undergrad and grad school. Applications were not yet due, but I was set on getting into a program and making international relations research into a career.

Globally, Iran was getting bolder with its nuclear program. President Obama, at a G20 summit, issued a warning:

Iran must comply with U.N. Security Council resolutions and make clear it is willing to meet its responsibilities as a member of the community of nations. We have offered Iran a clear path toward greater international integration if it lives up to its obligations, and that offer stands. But the Iranian government must now demonstrate through deeds its peaceful intentions or be held accountable to international standards and international law.

I remember watching Obama make that speech (which YouTube has preserved for posterity) and thinking that such a bargain would not work. Everything I had read at that point about credibility and commitment problems would suggest so. Why wouldn’t Iran simply take the short-term concessions and continue building a weapon anyway? No paper had constructed that exact expectation yet, and so I thought it would be a straightforward project.

Nevertheless, it would have to go on the backburner. I still needed to revise my existing writing sample and do grad applications.

4/2010: By this point, I had accepted an offer from the University of Rochester. I started fiddling around with modeling Obama’s deal and came to an interesting conclusion. It seemed that compliance was not only reasonable, it was rather easy to obtain. All the proposing country had to do was give concessions commensurate with what the potential proliferator would receive if it had nuclear weapons. The potential proliferator could not profit by breaking the agreement, as doing so would barely change what it was receiving but would cost all of the investment in proliferation. Meanwhile, as long as the potential proliferator could keep threatening to build weapons in the future, the proposer would not have incentive to cut the concessions either.

This project was a lot more interesting than I thought it would be!

8/8/2010: I moved to Rochester and got serious about trying to formalize the idea. The problem was that I had only taken a quarter of game theory before. So the process was … painful, especially in retrospect. I still have an image of my work from way back when:

I can make out some of what I was trying to do there. It is ugly. But I also think this is useful advice for new students. As a first year grad, you are in a very low stakes environment. Trying to do something and doing it poorly still gets you a foothold for later.

In any case, active progress on this was slow for the next couple of years. I had to take some classes to actually figure out what I was doing.

3/9/2012: I watched the previous night’s episode of The Daily Show for no real reason. In a remarkable stroke of luck, it featured an interview with Trita Parsi, an expert on U.S.-Iranian relations. He made some off-the-cuff remarks about Iran’s concerns of future U.S. preventive action. Fleshing out the logic further gave me the basis of Chapter 6 of my book, with an application to the Soviet Union.

9/2012: I made “The Invisible Fist” my second year paper. At the time, this was the biggest barrier for Rochester graduate students, but the idea from three years earlier got me through it.

The major criticism as I circulated the paper was that the model only explained why states should reach an agreement. And while nonproliferation agreements are fairly commonplace, so too are instances of countries developing nuclear weapons. Trying to simultaneously demonstrate that (1) agreements are credible and (2) other bargaining frictions might make states fail to reach a deal anyway was too much for a single article. I began looking for more explanations for bargaining failure beyond the one I had encountered for the Soviet Union.

5/17/2013: My dissertation committee felt that I had found enough other explanations, as I passed my prospectus defense. This was the first time I produced an outline that (more or less) matches what the book would ultimately look like.

12/2014: International Interactions R&R’d an article version of Chapter 6. It would later be published there. Tangible progress!

5/2015: Reading through the quantitative empirics of my book, Brad Smith suggested a better way to estimate nuclear proficiency. This eventually became our 𝜈-CLEAR paper. I would later replace the other measures of nuclear proficiency in the book with 𝜈.

6/10/2015: After two years of grinding through lots of math and writing, I defended my dissertation. Hooray, I became a doctor!

7/14/2015: The Joint Comprehensive Plan of Action—a.k.a. the Iran Deal—is announced. This was could not have been timed any better. Chapter 7 of my book was a theory without a case, only a roundabout discussion of the Iraq War. But the JCPOA nailed everything that the chapter’s theory predicted. I began revising that chapter.

8/2015: I began a postdoc at Stanford. My intention was to use the year to get the dissertation into a book manuscript and talk to publishers. But after six years of thinking about nuclear negotiations and not much else, I was really burned out. I still received excellent feedback on the project during the postdoc, but I set aside almost all of it. The year was productive for me overall, just not on the one dimension I had intended.

10/2015: The JCPOA went into effect. With nuclear negotiations all over the news, I hit the job market at exactly the right time.

7/2016: I moved to Pittsburgh. Remember that Obama speech in front of the G20? In what is a remarkable coincidence that bookends my journey, that summit was just a couple of miles away from where my office is now.

1/2017: I was still burned out. This became a moment of reflection, where I realized that 20 months had passed without making any progress on the manuscript. I convinced myself that if I didn’t get moving, the thing would hang over my head forever and not provide me any value toward a tenure case. So I cracked down and got to work.

3/2017: I sent an email to an editor at Cambridge. He quickly replied, and we set up a meeting at MPSA. Once in Chicago, he liked my pitch and asked to see a draft when I was ready.

5/22/2017: After making some final changes to the manuscript, I sent off a proposal, the introductory chapter, and the main theory chapter to Cambridge.

6/6/2017: My editor wrote back asking for the full manuscript to look over. I did so the next day. One day later, I saw an email notification on my phone that he had responded. I panicked—there is no way that a one-day response could be good news, right? But it was!

You may notice a theme developing here: my editor was fast.

9/6/2017: After three months, the reviewers come back with an R&R. Hooray!

Having published a few articles beforehand, the R&R process was not new to me. But it is an order of magnitude more complicated for book manuscripts. Article reviews are rarely more than a couple of pages. In contrast, I had twelve pages of comments to wade through for the book. This was daunting: a mountain of work and a lengthy road before any of it actually makes noticeable progress to any outside observer. After having gone through almost two years of burn out on the project, this had me slightly worried.

9/12/2017: I developed a solution to the problem that would work. The key for me to maintain focus and appreciate progress was to create a loooooong list of all the practical steps I had to take in revising the manuscript. By the end, I had a catalog of 70 things to do. I put that number on my whiteboard:

I dedicated at least a couple of hours every day to working on the book. Whenever I finished an item, I would go to the whiteboard and knock the number down by one. This gave me some tangible sense of progress even when the work ahead still seemed enormous. It also kept me focused on this project and resist the temptation to work on lower-priority projects that I could finish sooner.

11/28/2017: I sent the revised manuscript back.

1/28/2018: The remaining referee cleared the book. All the hard steps were over!

3/28/2019: I held the real thing in my hand for the first time.

So almost ten years later, I am all done with the project. I cannot describe how satisfying it was to move the book’s computer documents out of the active folder and into the archived folder. I can now finally put all of my effort into the other projects that have been pushed to the sidelines.

But with all of that said, ten years feels like a bargain. Some of that time was pure circumstances: I had to actually learn how to be a political scientist for a good portion of it. I was also an okay writer at the beginning of this, but now I feel that I have a much better grasp of how to communicate ideas.

Nevertheless, some portion of it was my own fault. I could have not put the project on the back burner for more than a year. I suppose if that was the price I had to pay to maintain my own sanity and happiness (and not work on something I was not into at the time), it was a deal well-worth taking.

I was also really, really fortunate with the review process. The first editor I spoke to was receptive of the project, and the reviewers I pulled liked it. Had that not been the case, it is easy to see how a ten year project could have turned into a twelve or thirteen year project. While I hope that future book projects will not last as long, I doubt this part will be as simple the next time around.

In any case, it feels great to finally be done!

You Can’t Put the Nuclear Cat Back in the Bag

Defense Secretary James Mattis has called for relief to North Korea to only come after it takes “irreversible steps to denuclearization.”

Let’s set aside the question of whether this will happen. It probably won’t. The United States cannot credibly commit to not invade a nuclear-free North Korea under the right circumstances, and so North Korea will keep its deterrent to hedge against that. And even if that credible commitment were not a concern, the ability to build nuclear weapons drives concessions. North Korea would not agree to “irreversible” denuclearization if only to maintain its ability to leverage the threat to build again.

Instead, let’s focus on a more interesting question: can you make nuclear proliferation irreversible? This is difficult to answer because you first need to somehow quantify a state’s nuclear proficiency. One cannot observe proficiency directly, only behaviors consistent with low or high proficiency.

Fortunately, Brad Smith and I have developed a measure of this. ν-CLEAR takes observable nuclear behaviors and uses that information to estimate a country’s nuclear proficiency. We are currently working on a massively expanded version of the data, and one of our findings speaks to the situation with North Korea.

Consider the role of uranium enrichment and reprocessing on nuclear proliferation. This is a critical step toward actually building a nuclear weapon. Bombs need fuel, and to have fuel you need to either enrich uranium or reprocess plutonium from spent uranium. The Yongbyon Nuclear Scientific Research Center has such a facility. Any deal like what the Trump administration hopes for would involve shutting this down.

However, shutting down a facility does not necessarily make nuclear proliferation irreversible. Unless actually operating an enrichment or reprocessing facility radically shifts a country’s nuclear proficiency, North Korea could just construct a new one.

Our data and a little bit of historical knowledge can help us understand the relationship between fuel facilities and nuclear proficiency. Argentina operated its Pilcaniyeu Enrichment Facility until 1994. Let’s look at a timeline of Argentina’s nuclear proficiency before and after. Larger values mean greater proficiency:

Closing the facility had an effect. But it’s marginal. Let’s zoom in on 1994:

Argentina’s proficiency score definitely drops. However, operating the facility is only of marginal importance.

What is going on here? The issue is that having a facility and knowing how to create a facility are two different things. A country that builds fuel fabrication centers also has the nuclear capacity to engage in other nuclear activities. Our estimation procedure incorporates those factors into a state’s overall score. When a state shuts down those facilities, the procedure penalizes that state’s score. But it also recognizes the state’s other nuclear activities as evidence of its ability to rebuild a facility if it wanted to. As a result, ν does not believe that operation of the facility tells us much about what Argentina can or cannot do.

Bringing this back to North Korea, it is unlikely that any sort of divestment will irreversibly cancel North Korea’s nuclear weapons program. For these purposes, knowing how to do things is more important than actually doing them. As long as North Korean nuclear scientists retain their knowledge, Peongyang will always be able to restart the program.

As a final note, to be clear, I am not suggesting that the U.S. should ignore the importance of the Yongbyon Nuclear Scientific Research Center. When Donald Trump meets Kim Jong-un, it should be an important topic of discussion. The ν measure only captures what states can do. It does not care much about time delays. Shuttering Yongbyon would probably not reduce North Korea’s ability to develop more fuel. But it would increase the time necessary to do that because North Korea would have to rebuild the facility. And that’s a goal worth obtaining.

Does Increasing the Costs of Conflict Decrease the Probability of War?

According to many popular theories of war, the answer is yes. In fact, this is the textbook relationship for standard stories about why states would do well to pursue increased trade ties, alliances, and nuclear weapons. (I am guilty here, too.)

It is easy to understand why this is the conventional wisdom. Consider the bargaining model of war. In the standard set-up, one side expects to receive p portion of the good in dispute, while the other receives 1-p. But because war is costly, both sides are willing to take less than their expected share to avoid conflict. This gives rise to the famous bargaining range:

Notice that when you increase the costs of war for both sides, the bargaining range grows bigger:

Thus, in theory, the reason that increasing the costs of conflict decreases the probability of war is because it makes the set of mutually preferable alternatives larger. In turn, it should be easier to identify one such settlement. Even if no one is being strategic, if you randomly throw a dart on the line, additional costs makes you more likely to hit the range.

Nevertheless, history often yields international crises that run counter to this logic like trade ties before World War I. Intuition based on some formalization is not the same as solving for equilibrium strategies and taking comparative statics. Further, while it is true that increasing the costs of conflict decrease the probability of war for most mechanisms, this is not a universal law.

Such is the topic of a new working paper by Iris Malone and myself. In it, we show that when one state is uncertain about its opponent’s resolve, increasing the costs of war can also increase the probability of war.

The intuition comes from the risk-return tradeoff. If I do not know what your bottom line is, I can take one of two approaches to negotiations.

First, I can make a small offer that only an unresolved type will accept. This works great for me when you are an unresolved type because I capture a large share of the stakes. But if also backfires against a resolved type—they fight, leading to inefficient costs of war.

Second, I can make a large offer that all types will accept. The benefit here is that I assuredly avoid paying the costs of war. The downside is that I am essentially leaving money on the table for the unresolved type.

Many factors determine which is the superior option—the relative likelihoods of each type, my risk propensity, and my costs of war, for example. But one under-appreciated determinant is the relative difference between the resolved type’s reservation value (the minimum it is willing to accept) and the unresolved type’s.

Consider the left side of the above figure. Here, the difference between the reservation values of the resolved and unresolved types is fairly small. Thus, if I make the risky offer that only the unresolved type is willing to accept (the underlined x), I’m only stealing slightly more if I made the safe offer that both types are willing to accept (the bar x). Gambling is not particularly attractive in this case, since I am risking my own costs of war to attempt to take a only a tiny additional amount of the pie.

Now consider the right side of the figure. Here, the difference in types is much greater. Thus, gambling looks comparatively more attractive this time around.

But note that increasing the military/opportunity costs of war has this precise effect of increasing the gap in the types’ reservation values. This is because unresolved types—by definition—view incremental increases to the military/opportunity costs of war as larger than the resolved type. As a result, increasing the costs of conflict can increase the probability of war.

What’s going on here? The core of the problem is that inflating costs simultaneously exacerbates the information problem that the proposer faces. This is because the proposer faces no uncertainty whatsoever when the types have identical reservation values. But increasing costs simultaneously increases the bandwidth of the proposer’s uncertainty. Thus, while increasing costs ought to have a pacifying effect, the countervailing increased uncertainty can sometimes predominate.

The good news for proponents of economic interdependence theory and mutually assured destruction is that this is only a short-term effect. In the long term, the probability of war eventually goes down. This is because sufficiently high costs of war makes each type willing to accept an offer of 0, at which point the proposer will offer an amount that both types assuredly accept.

The above figure illustrates this non-monotonic effect, with the x-axis representing the relative influence of the new costs of war as compared to the old. Note that this has important implications for both economic interdependence and nuclear weapons research. Just because two groups are trading with each other at record levels (say, on the eve of World War I) does not mean that the probability of war will go down. In fact, the parameters for which war occurs with positive probability may increase if the new costs are sufficiently low compared to the already existing costs.

Meanwhile, the figure also shows that nuclear weapons might not have a pacifying effect in the short-run. While the potential damage of 1000 nuclear weapons may push the effect into the guaranteed peace region on the right, the short-run effect of a handful of nuclear weapons might increase the circumstances under which war occurs. This is particularly concerning when thinking about a country like North Korea, which only has a handful of nuclear weapons currently.

As a further caveat, the increased costs only cause more war when the ratio between the receiver’s new costs and the proposer’s costs is sufficiently great compared to that same ratio of the old costs. This is because if the proposer faces massively increased costs compared to its baseline risk-return tradeoff, it is less likely to pursue the risky option even if there is a larger difference between the two types’ reservation values.

Fortunately, this caveat gives a nice comparative static to work with. In the paper, we investigate relations between India and China from 1949 up through the start of the 1962 Sino-Indian War. Interestingly, we show that military tensions boiled over just as trade technologies were increasing their costs for fighting; cooler heads prevailed once again in the 1980s and beyond as potential trade grew to unprecedented levels. Uncertainty over resolve played a big role here, with Indian leadership (falsely) believing that China would back down rather than risk disrupting their trade relationship. We further identify that the critical ratio discussed above held—that is, the lost trade—evenly impacted the two countries, while the status quo costs of war were much smaller for China due to their massive (10:1 in personnel alone!) military advantage.

Again, you can view the paper here. Please send me an email if you have some comments!

Abstract. International relations bargaining theory predicts that increasing the costs of war makes conflict less likely, but some crises emerge after the potential costs of conflict have increased. Why? We show that a non-monotonic relationship exists between the costs of conflict and the probability of war when there is uncertainty about resolve. Under these conditions, increasing the costs of an uninformed party’s opponent has a second-order effect of exacerbating informational asymmetries. We derive precise conditions under which fighting can occur more frequently and empirically showcase the model’s implications through a case study of Sino-Indian relations from 1949 to 2007. As the model predicts, we show that the 1962 Sino-Indian war occurred after a major trade agreement went into effect because uncertainty over Chinese resolve led India to issue aggressive screening offers over a border dispute and gamble on the risk of conflict.

The Power Shift Myth: Understanding Preventive War

Shifting power is often cited as an explanation for war. But the causal mechanism isn’t so straightforward.

While the concept of preventive war dates back to Thucydides’ and The History of the Peloponnesian War, the modern understanding is just barely in its third decade. In Rationalist Explanations for War, James Fearon conclusively shows that bargained settlements exist that leave both parties better off than had they fought. The puzzle of war is why wars occur despite this inefficiency.

One of Fearon’s answers is that power may shift over time. Although a rising state and a declining state may reach an efficient bargain in the future, the declining state may be better off securing a costly but advantageous outcome through war today. As much as the rising state might protest, it cannot credibly commit to maintaining the status quo distribution of benefits. Rather, it will eventually want to exploit its new found power by shifting the benefits in its favor.

This idea has taken off in international relations literature. It is now the textbook explanation of preventive war. (See Frieden, Lake, and Schultz, Kydd, or myself.) It also has obvious empirical implications—growing power implies more war—which many quantitative scholars have explored. (See Bell and Johnson, Schub, and Fuhrmann and Kreps for recent examples.) The literature is growing, and knowledge is accumulating. These are great things to see.

A Hidden Assumption
Unfortunately, the causal mechanism behind preventive war isn’t entirely clear, and the notion that power shifts alone cause war is a bit of a myth. One hidden assumption in the simple preventive war construction is that power growth is exogenous. That is, the rising state does not choose whether to grow or how. It simply does, as though power grows on trees.

Yet, in practice, most power shifts are endogenous. Raising an army, building new aircraft carriers, investing in missile defense, and designing nuclear weapons all require active decisions by the state. The basic model ignores this part of the process and instead jumps to the strategic tradeoffs once the state has decided how to shift power.

Thus, a natural question to ask is how endogenous power shifts impact the probability of war. Thomas Chadefaux addresses this in his aptly-titled Bargaining over Power article. Perhaps surprisingly, the war result reverses completely—in any instance that a preventive war would have been fought, bargaining over power leads to a peaceful outcome.

The intuition is straightforward once you work through the mathematical logic. A rising state really wants to avoid war today because fighting would take place on terms most disadvantageous to it. Thus, if it had to choose between undertaking a power shift that would induce preventive war and a smaller power shift that the declining state would acquiesce to, it would choose the latter. After all, a smaller (but realized) power shift is preferable to a costly war.

The New Puzzle
Of course, Chadefaux’s results only take us further down the rabbit hole. There is ample historical evidence to tell us that states fight wars to forestall shifts in power. What then actually causes preventive war?

The literature provides a variety of answers, which I will now attempt to synthesize. First, some power shifts may actually be exogenous. If demographic trends are at the root of a power shift, countries may be unable to effectively limit their future power. In civil conflicts, protesters may be unable resolve coordination problems in the near future, leading to dramatic shifts in power over a short period of time. This helps explain why autocratic regimes exert such great effort in controlling their citizens’ movements.

Fearon recognized that the commitment problem disappears when states can bargain over power. But when the object of value also confers military advantages, bargaining can break down when there are indivisibilities in the good. Chadefaux also showed that having distinct discount factors can lead to conflict even without those indivisibilities.

Implementing such an agreement may create other bargaining problems, too. Debs and Monteiro investigate a model with costly power shifts that declining states cannot effectively monitor. Declining states sometimes need to initiate wars so as to deter weapons construction they might not otherwise observe. My research looks to see whether offering concessions-for-weapons can resolve these issues. Fortunately, the answer is yes. However, in the book manuscript I am working on, such deals fail when there is uncertainty over the declining state’s willingness to intervene.

Undoubtedly, there are many more answers to why states fight preventive wars even when power shifts are endogenous. Sadly, though, this literature feels somewhat stifled given that new research often constructs models with exogenous power shifts without any justification for why states cannot negotiate over power.

Empirical Implications
I conclude by discussing some implications of endogenous power shifts. First, quantitative scholars should care greatly about bargaining over power. Although we have established connections between power shifts and war, the above theory indicates that the causal relationship is not obvious. For example, it might be that other bargaining problems cause to both power shifts and war. We need to think carefully about these higher-order issues and search for empirical evidence of them.

Policy-wise, this tells us a great deal about negotiations with Iran. If Tehran constructs a nuclear weapon, it must be doing so because it does not anticipate preventive war. Thus, one way the United States can hold Iran to its commitments under the Joint Comprehensive Plan of Action is to maintain a credible threat to fight a war should Tehran violate the agreement. Internalizing the threat, Iran would not build a weapon. This is perhaps the ideal for Washington—the American threat to invade does all the heavy lifting, allowing the United States to obtain its best policy outcome without actually paying the costs of war.

rationcover

Understanding the Iran Deal: A Model of Nuclear Reversal

Most of the discussion surrounding the Joint Comprehensive Plan of Action (JCPOA, or the “Iran Deal”) has focused on mechanisms that monitor Iranian compliance. How can we be sure Iran is using this facility for scientific research? When can weapons inspectors show up? Who gets to take the soil samples? These kinds of questions seem to be the focus.

Fewer people have noted Iran’s nuclear divestment built into the deal. Yet Iran is doing a lot here. To wit, here are some of the features of the JCPOA:

  • At the Arak facility, the reactor under construction will be filled with concrete, and the redesigned reactor will not be suitable for weapons-grade plutonium. Excess heavy water supplies will be shipped out of the country. Existing centrifuges will be removed and stored under round-the-clock IAEA supervision at Natanz.
  • The Fordow Fuel Enrichment Plant will be converted to a nuclear, physics, and technology center. Many of its centrifuges will be removed and sent to Natanz under IAEA supervision. Existing cascades will be modified to produce stable isotopes instead of uranium hexafluoride. The associated pipework for the enrichment will also be sent Natanz.
  • All enriched uranium hexafluoride in excess of 300 kilograms will be downblended to 3.67% or sold on the international market.

Though such features are fairly common in arms agreements, they are nevertheless puzzling. None of this makes proliferation impossible, so the terms cannot be for that purpose. But they clearly make proliferating more expensive, which seems like a bad move for Iran if it truly wants to build a weapon. On the other hand, if Iran only wants to use the proliferation threat to coerce concessions out of the United States, this still seems like a bad move. After all, in bargaining, the deals you receive are commensurate with your outside options; make your outside options worse, and the amount of stuff you get goes down as well.

The JCPOA, perhaps the worst formatted treaty ever.

The JCPOA, perhaps the most poorly formatted treaty ever.

What gives? In a new working paper, I argue that undergoing such a reversal works to the benefit of potential proliferators. Indeed, potential proliferators can extract the entire surplus by divesting in this manner.

In short, the logic is as follows. Opponents (like the United States versus Iran) can deal with the proliferation problem in one of two ways. First, they can give “carrots” by striking a deal with the nuclearizing state. These types of deals provide enough benefits to potential proliferators that building weapons is no longer profitable. Consequently, and perhaps surprisingly, they are credible even in the absence of effective monitoring institutions.

Second, opponents can leverage the “stick” in the form of preventive war. The monitoring problem makes this difficult, though. Sometimes following through on the preventive war threat shuts down a real project. Sometimes preventive war just a bluff. Sometimes opponents end up fighting a target that was not even investing in proliferation. Sometimes the potential proliferator can successfully and secretly obtain a nuclear weapon. No matter what, though, this is a mess of inefficiency, both from the cost of war and the cost of proliferation.

Naturally, the opponent chooses the option that is cheaper for it. So if the cost of preventive war is sufficiently low, it goes in that direction. In contrast, if the price of concessions is relatively lower, carrots are preferable.

Note that one determinant of the opponent’s choice is the cost of proliferating. When building weapons is cheap, the concessions necessary to convince the potential proliferator not to build are very high. But if proliferation is very expensive, then making the deal looks very attractive to the opponent.

This is where nuclear reversals like those built into the JCPOA come into play. Think about the exact proliferation cost that flips the opponent’s preference from sticks to carrots. Below that line, the inefficiency weighs down everyone’s payoff. Right above that line, efficiency reigns supreme. But the opponent is right at indifference at this point. Thus, the entire surplus shifts to the potential proliferator!

The following payoff graph drives home this point. A is the potential proliferator; B is the opponent; k* is the exact value that flips the opponent from the stick strategy to the carrot strategy:

Making proliferation more difficult can work in your favor.

Making proliferation more difficult can work in your favor.

If you are below k*, the opponent opts for the preventive war threat, weighing down everyone’s payoff. But jump above k*, and suddenly the opponent wants to make a deal. Note that everyone’s payoff is greater under these circumstances because there is no deadweight loss built into the system.

Thus, imagine that you are a potential proliferator living in a world below k*. If you do nothing, your opponent is going to credibly threaten preventive war against you. However, if you increase the cost of proliferating—say, by agreeing to measures like those in the JCPOA—suddenly you make out like a bandit. As such, you obviously divest your program.

What does this say about Iran? Well, it indicates that a lot of the policy discussion is misplaced for a few of reasons:

  1. These sorts of agreements work even in the absence of effective monitoring institutions. So while monitoring might be nice, it is definitely not necessary to avoid a nuclear Iran. (The paper clarifies exactly why this works, which could be the subject of its own blog post.)
  2. Iranian refusal to agree to further restrictions is not proof positive of some secret plan to proliferate. Looking back at the graph, note that while some reversal works to Iran’s benefit, anything past k* decreases its payoff. As such, by standing firm, Iran may be playing a delicate balancing game to get exactly to k* and no further.
  3. These deals primarily benefit potential proliferators. This might come as a surprise. After all, potential proliferators do not have nuclear weapons at the start of the interaction, have to pay costs to acquire those weapons, and can have their efforts erased if the opponent decides to initiate a preventive war. Yet the potential proliferators can extract all of the surplus from a deal if they are careful.
  4. In light of (3), it is not surprising that a majority of Americans believe that Iran got the better end of the deal. But that’s not inherently because Washington bungled the negotiations. Rather, despite all the military power the United States has, these types of interactions inherently deal us a losing hand.

The paper works through the logic of the above argument and discusses the empirical implications in greater depth. Please take a look at it; I’d love to hear you comments.

Bargaining Power and the Iran Deal

Today’s post is not an attempt to give a full analysis of the Iran deal.[1] Rather, I just want to make a quick point about how the structure of negotiations greatly favors the Obama administration.

Recall the equilibrium of an ultimatum game. When two parties are trying to divide a bargaining pie and one side makes a take-it-or-leave-it offer, that proposer receives the entire benefit from bargaining. In fact, even if negotiations can continue past a single offer, as long as a single person controls all of the offers, the receiver still receives none of the surplus.

This result makes a lot of people feel uncomfortable. After all, the outcomes are far from fair. Fortunately, in real life, people are rarely constrained in this way. If I don’t like the offer you propose me, I can always propose a counteroffer. And if you don’t like that, nothing stops you from making a counter-counteroffer. That type of negotiations is called Rubinstein bargaining, and it ends with a even split of the pie.

In my book on bargaining, though, I point out that there are some prominent exceptions where negotiations take the form of an ultimatum game. For example, when returning a security deposit, your former landlord can write you a check and leave it at that. You could try suggesting a counteroffer, but the landlord doesn’t have to pay attention—you already have the check, and you need to decide whether that’s better than going to court or not. This helps explain why renters often dread the move out.

Unfortunately for members of Congress, “negotiations” between the Obama administration and Congress are more like security deposits than haggling over the price of strawberries at a farmer’s market. If Congress rejects the deal (which would require overriding a presidential veto), they can’t go to Iran and negotiate a new deal for themselves. The Obama administration controls dealings with Iran, giving it all of the proposal power. Bargaining theory would therefore predict that the Obama administration will be very satisfied[2], while Congress will find the deal about as attractive as if there were no deal at all.

And that’s basically what we are seeing right now. Congress is up in arms over the deal (hehe). They are going to make a big show about what they claim is an awful agreement, but they don’t have any say about the terms beyond an up/down vote. That—combined with the fact that Obama only needs 34 senators to get this to work—means that the Obama administration is going to receivea very favorable deal for itself.

[1] Here is my take on why such deals work. The paper is a bit dated, but it gets the point across.

[2] I mean that the Obama administration will be very satisfied by the deal insofar as it relates to its disagreement with Congress. It might not be so satisfied by the deal insofar as it relates to its disagreement with Iran.