## Welcome!

Graduated from the University of California, San Diego in 2009. Currently a PhD candidate at the University of Rochester.

Interested in formal models of inter-state conflict.

You may know me from my textbook (Game Theory 101: The Complete Textbook), my other website (gametheory101.com), my game theory videos on YouTube, or Freakonomics.

## Crimea and Ukrainian Nuclear Nonsense

For whatever reason, it seems trendy to blame Ukraine’s current predicament on its 1994 decision to denuclearize. If Ukraine had proliferated, the logic goes, then Russia would not have invaded Crimea, and people in Kiev would be a lot happier.

The trouble is, none of this makes any sense. To be kind, these arguments rely on an awkward reading of history and assume that nuclear weapons are a magical cure-all. The issues are threefold:

1) Ukraine never had command control over nuclear weapons. Yes, there were a lot of nuclear weapons sitting on Ukrainian soil–the third most in the world at that time after the United States and Russia. But having weapons on your soil is meaningless unless you can authorize their use. Trying to obtain control over those weapons would have required force and therefore war with Russia, which, as Anton Strezhnev points out, would not have made much sense for Ukraine. At no point in time could leaders in Kiev flip a magic switch and turn on a nuclear deterrent.

So if Ukraine wanted nuclear weapons, it was going to have to work hard for them. Trouble is…

2) Building its own nuclear deterrent would have been insane. Fresh off the fall of the Soviet Union, the Ukrainian economy was hurting. Spending tons of money developing its own nuclear weapons program would have put the country in a much deeper red hole. Still, because deterrence had value, Ukraine used the nuclear issue to extract financial compensation from the West. Meanwhile, Russia offered to ship Ukraine downblended uranium to keep their nuclear power plants firing. (There were also territorial agreements that Russia is currently violating, but no one at the time reasonably believed that those terms would hold up during exceptional situations.) Nuclearization would have killed those inducements and perhaps put Ukraine in such economic peril that it seems doubtful that we would have wound up in the position we are in today.

And even if the Ukrainian economy miraculously healed and we somehow managed to find ourselves in the duplicate situation…

3) It isn’t clear how nuclear weapons would have deterred Russia. Let’s not forget Russia has a nuclear stockpile as well. It is hard to see how Ukraine could have credibly threatened nuclear retaliation in response to the invasion of Crimea. Nuclear weapons are great at deterring aggression toward vital assets. I am not sure that Crimea counts, especially since it has such heavy Russian population. A nuclear deterrent might stop Putin from pushing further west toward Kiev, but he might very well be stopping where he is anyway due to conventional threats and economic warfare from the West.

TL;DR: It is really hard to claim that Ukraine’s decision to not proliferate in the 1990s was a mistake.

It is interesting–if unfortunate–to be watching international bargaining unfolding right in front of our eyes. Russia has seized the Crimean Peninsula, which has the awkward characteristics of being (1) on Ukraine’s southeastern fringe, (2) on Russia’s border, (3) predominantly inhabited by Russian speakers, and (4) the home of a Russian naval fleet.

Although where the crisis goes in in the next couple of days is anyone’s guess, Putin is engaging in a classic example of the risk-return tradeoff. International conflict–whether economic or militaristic–is costly for all parties involved. These costs incentivize the actors to reach negotiated settlements. After all, if everyone knows how conflict would end, they could implement that solution from the start and preserve the costs of fighting. Everyone finishes better off.

Unfortunately, combatants are not always certain of each other’s capabilities and willingness to fight. Putin, for example, might know that he can take some of Crimea without triggering war from Kiev or massive economic sanctions from the West, but he likely does not know the maximum Russian expansion those parties are willing to tolerate.

So how does Putin decide where to stop? The risk-return tradeoff provides some guidance. Bargaining positions range from conservative to aggressive. Adopting a conservative position means that other parties are less likely to reject your demands and fight a war or impose economic sanctions. While this is a safe choice, conservative positions are inherently costly because you must concede a lot to the opposition in the process. Alternatively, you could act more aggressively and try to take more. This pays off greatly when your plan succeeds and the other side concedes but risks backfiring if the other side rejects your demands and inflicts war/sanctions costs on you.

Ultimately, you have to weigh the risks of rejection to the high potential returns of capturing larger portions of the stakes. If the reward is great relative to the risk, you should adopt an aggressive position. If it is small, you should go conservative. If it is somewhere in between, you should take a moderate approach.

In this light, taking the Crimea was a relatively safe choice for Putin; given its population’s heavy Russian sympathies, any local resistance would have been minimal. It also has more value than other regions because of its positioning along the Black Sea. But as Russia advances to the northwest, it will find fewer sympathizers and more West-loyal Ukrainians. (Here is a useful map of the 2004 election results; purple is a decent proxy for Russian affinity.) This not only makes incremental gains more costly for Putin but also risks exceeding the most the West and Kiev is willing to give up. As a result, Putin might go a little further west, but don’t be surprised if this has a natural, peaceful, and relatively moderate outcome.

## The Nefarious Reason to Draw on Jeopardy

Arthur Chu, current four-day champion on Jeopardy!, has made a lot of waves around the blogosphere with his unusual play style. (Among other things, he hunts all over the board for Daily Doubles, has waged strange dollar amounts when getting one, and clicks loudly when ringing in.) What has garnered the most attention, though, is his determination to play for the draw. On three occasions, Arthur has had the opportunity to bet enough to eliminate his opponent from the show. Each time, he has bet enough so that if his opponent wagers everything, he or she will draw with Arthur.

It is worth noting that draws aren’t the worst thing in Jeopardy. Unlike just about all other game shows, there is no sudden death mechanism. Instead, both players “win” and become co-champions, keeping the money accumulated from that game and coming back to play again the next day. There is no cost to you as the player; Jeopardy! foots the bill.

Why is Arthur doing this? The links provided above give two reasons. First, there have been instances where betting $1 more than enough to force a draw has resulted in the leader ultimately losing the game. Betting more than the absolute minimum necessary to ensure that you get to stay the next day thus has some risks. Second, if your opponents know that you will bet to draw, it induces them to wager all of their money. This is advantageous to the leader in case everyone gets the clue wrong. That second point might be a little complicated, so an example might help. Suppose the leader had$20,000, second place had $15,000, and third place died in the middle of the taping. If the leader wagers$10,000, second place might sensibly wager $15,000 to force the draw if she thought she had a good chance of responding correctly. If only one is correct, that person wins. If they are both right, they draw. If both are wrong, second place goes bankrupt and the leader wins with$10,000.

Compare that to what happens if the leader wagers $10,001 (enough to guarantee victory with a correct response) and second place wagers$5,000. All outcomes remain the same except when both are wrong. Now the leader drops to $9,999 and the person trailing previously wins with$10,000.

Sure, these are good reasons to play to draw, but I think there is something more nefarious going on. Arthur knows he is better than the contestants he has been beating. One of the easiest ways to lose as Jeopardy! champion is to play a game against someone who is better than you. So why would you want to get rid of contestants that you are better than? Creating a co-champion means that the producers will draw one less person from the contestant pool for the next game, meaning there is one less chance you will play against someone better than you. This is nefarious because it looks nice–he is allowing second place to take home thousands and thousands of dollars more than they would be able to otherwise–but really he is saying “hey, you are bad at this game, so please keep playing with me!”

In addition, his alleged kindness might even be reciprocated one day. Perhaps someone he permits a draw to will one day have the lead going into Final Jeopardy. Do you think that contestant is going to play for the win or the draw? Well, if Arthur is going to keep that person on the gravy train for match after match, I suspect that person is going to give Arthur the opportunity to draw.

It’s nefarious. Arthur’s draws could spread like some sort of vile plague.

## Misconceptions about the Syrian Civil War

If I had to guess what the three most common explanations are for the Syrian Civil War, I would go with:

1. Ethnic fractionalization
2. Economic inequality
3. The Arab Spring

The problem is, none of these are good explanations. This post explains why.

First, some background. “Rationalist Explanations for War” is one of IR’s most-cited articles from the past twenty years, and for good reason. In it, James Fearon shows that the costs of war ensure that a range of settlements mutually preferable to war always exists. The takeaway point is very simple: you can have massive grievances against a rival, but those grievances do not explain why you go to war. Many countries have internal strife of this nature. Very few of them actually resolve their problems on the battlefield. After all, the parties could implement whatever the expected end result of the fighting would be before the war starts. No one has incentive to fight at that point, since they would receive an identical outcome in expectation but suffer the costs of war (not to mention risk death).

So what does this have to say about the standard explanations for the Syrian Civil War?

Ethnic Fractionalization
Syria’s population is 60% Sunni and 12% Alawite. The Alawites (i.e., Bashar al-Assad) are in power. War allegedly started because of this massive disparity.

This is a bad explanation for two reasons. First, ethnic fractionalization in Syria has existed all along. So if it caused the war in 2011, why did it not cause the war in 2010, 2009, 2008, or 2007? You can’t explain variation (peace/war) with a constant (fractionalization), yet this is exactly what this argument attempts to do.

Second, fractionalization is only a problem because of political repression. The United States is 63% White and 13% African American with an African American in power but is no where near war because of the lack of oppression. (Technically Obama is half-half, but he identifies as African American.) So if ethnic fractionalization leading to oppression caused the war, you are still left trying to explain why Assad simply didn’t relax the extent of oppression. The majority Sunni population would be pacified, and Assad wouldn’t be risking his life fighting a war. Both sides would appear better off.

Economic Inequality
Economic inequality in Syria is bad. For the latest data I could find, Syria’s Gini coefficient is .358 (2004, World Bank). War allegedly started because the impoverished had grievance.

This is a bad explanation for the same two reasons as above. First, this inequality has persisted for a long time. It’s hard to explain why war did not start in 2010, 2009, 2008, or 2007 but did in 2011. Second, if inequality was such a big deal, why didn’t Assad simply throw money at the impoverished groups? After all, those suffering are fighting (in theory) for better economic opportunities. Assad could just give them those opportunities, avoid the bloody mess, and not be risking his life. Again, all sides would appear better off.

Also, it’s worth noting that the United States’ Gini coefficient is .45 (2007, World Bank), making the U.S. more unequal than Syria.

The Arab Spring
The Arab Spring provides a better explanation than the first two because it didn’t exist in 2007, 2008, 2009 or the first eleven months of 2010 but did have effect after that point. Consequently, variation of the presence of the Arab Spring can explain variation in the peace/war outcome.

On the other hand, there is still a question of why the Assad regime couldn’t appease the protesters’ demands peacefully for the same reasons as above. In fact, Qatar did something to that effect, giving raises to key groups (including 120% increases to military officers) to preempt the need to protest.

The Simplest Explanation
The simple explanation of the Syrian Civil War is as follows. The Arab Spring acted as a coordination mechanism and/or allowed disenfranchised groups to overcome their collective action problem. This gave the protesters a sudden spike in military power. For Assad to resolve the tensions, he would have to credibly commit to giving up concessions in the long term. However, once the protesters all went home and Arab Spring coordination effect died, he would no longer have reason to continue giving those concessions. So the protesters became rebels, knowing that war and regime change were the only way to secure concessions.

The Syrian Civil War is, in effect, a preventive war.

This post is based on a lecture I produced for my Civil Wars MOOC, seen below:

## Bluffing, Arms Treaties, and Preventive War

I have a new chapter from my book project available. Here’s the abstract:

With complete information, rising states internalize declining states’ threats to launch preventive war. If that threat is credible, they do not pursue arms programs to avoid conflict. If that threat is incredible, declining states preemptively engage in bargaining to override the need to build those weapons, extracting the surplus in the process. Either way, no arms construction occurs. This paper investigates how negotiations work when that threat to intervene is uncertain. When rising states believe their rivals are strong, weak declining states can convince rising states not to build without offering any concessions by mimicking the strong type. When rising states are skeptical, inefficiency prevails. To keep the weak types honest, rising states sometimes attempt to build arms after receiving unencouraging signals. Weak types allow the power shift to transpire. Strong types respond with preventive war. The results indicate that many “preventive” wars are the result of information problems, \textit{not} commitment problems.

You can read the full chapter here. It has a number of important policy implications about Israeli behavior toward Iran’s nuclear program. I think I will write a post on those next week.

## Robustness Checks in Formal Models

One thing I really like about large-n empirical papers is their ability to run robustness checks. Statistical models only produce the ideal results if the author captures the correct data generating process. For example, suppose a researcher theorizes that states with larger economies have higher chances of winning wars. If the size of economies and regime type are the only things that matter for winning a war, then you would want your model of war winning to just include economic size and regime type.

However, someone might object under the belief that industrial capacity matters as well. It might be difficult to know who is correct, but fortunately there is an easy solution: just run both models. If the size of the economy is positively correlated with winning wars in both cases, then the objection is irrelevant, the scholars can agree to disagree, and we can go back on focusing on the economy.

So despite only focusing on one model, empirical researchers usually include a few robustness checks within a paper and often include a much larger online appendix with yet more robustness checks. This should be applauded, as it gives us more confidence that the result is correct.

Yet formal theorists often fail to make such robustness checks–even though the problem is the same one empiricists face. Indeed, formal theorists tend to give us the result of one model. But that model is essentially a knife-edge case of a greater family of models, one in which the order of moves is reversed, players have additional moves, and information operates differently. And just like the empirical problem, it is very difficult for formal theorists to “know” that their version of the model is the correct game that real world actors play. Why, then, should we privilege the single version that the author presents? This is an especially important question given that authors have incentive to present the model with the most interesting results even if those results completely disappear if the author tweaks the assumptions slightly. (Note, again, that this is the empiricists have the same incentives.)

The answer, of course, is that we should not. We should expect formal theorists to think long and hard about the models they create and whether they actually represent a broad, robust finding.

For example, consider my work on nuclear nonproliferation agreements. I show that potential nuclear powers are always willing to accept nonproliferation settlements. That is an extremely broad and strong claim. And, dangerously, it comes from a very simple bargaining game. Why should you trust my results?

If that is all I presented to you, you probably should not. Observers of American/Iranian negotiations know that there are a lot of complexities to this type of bargaining. Consequently, I have received a large number of questions about how the results would change if I tweaked certain assumptions. I collected most of these in the back of my brain in case someone were to ask me those questions again.

But then my presentation at the annual Peace Science Society conference approached. For those unaware, Peace Science tends to slant very empirical. So as I was thinking about how to present the paper, I began considering how a strict empiricist would present the paper. She would probably start with a bit of theory, show the results of the main model, demonstrate robustness (or at least say “this is robust to…”), and then perhaps talk about a couple of cases if time permitted.

Theorists and empiricists may be different in many ways, but I think it is telling that the previous sentence could apply equally to both a theoretical and an empirical presentation. Yet theorists almost always completely skip the robustness step. This time, I did not. So instead of saying “bargaining works in the model I constructed,” I said “bargaining works in the model I constructed and in models with the following different assumptions.” I then showed a slide with the following:

• Prior investment in nuclear research
• Prestige
• Punishment for reneging
• Negative externalities
• Non-binary power shifts
• Nondeterministic proliferation
• Sanctions
• Bargaining over objects that influence future bargaining power
• Non-common discount factors
• Imperfect monitoring

This is much, much, much stronger than just saying “hey, bargaining works.” I think it won over a few people in the crowd, and I received many comments after the presentation about how it was a nice touch.

All of this is to say that we really should be making robustness checks of our formal models both in our papers and in our presentations. Why isn’t this commonplace already? There are two restricting factors. First, solving alternative model specifications is a time consuming task. An empiricist can just add a few robustness check variables, press a button, and be done. (This assumes that such data already exist. If not, they are in trouble.) Theorists often have to re-solve the entire model, which can take days.

Second, it is space consuming. I mentioned ten robustness checks above. The paper takes ten and a half pages addressing all of them. I can get away with this because I am writing a book; I would be in deep trouble if this were a journal article and I only had 10,000 words to work with.

Still, I don’t think either of these are particularly good excuses. Regarding time: yes, spending time doing these things is annoying. But it is an investment in getting your result right, and you should be willing to pay it. Moreover, if the central result you are finding is decent, then the logic should intuitively carry over in many of the cases. For example, Maya Sen and I have a working paper on judicial nominations that shows under certain conditions Senators randomly reject nominees despite not having any good reason to do so. We use a very simple model, yet (much to our surprise) the results immediately carry over to much more complicated setups, and we can explain why without having to do any more math.

Regarding space: this is a poor excuse. Empiricists solve the space problem by creating online appendices. When was the last time you ever saw an online appendix for a formal article that wasn’t just a proof of the model in the paper? There is no reason theorists can’t copy this solution.

Bottom line: empiricists and theorists face similar robustness challenges. We need our models to be robust, and the only way we can effectively communicate that in scholarly work is to conduct robustness checks. Empiricists do a good job here; theorists have a lot of room for improvement.

## Assorted Thoughts on Iran

Here’s a story in poor timing. I’ve spent the last three years writing a dissertation on bargaining over nuclear weapons, often with Iran as substantive motivation and focus. On Saturday night, my best friend from high school was getting married. Also on Saturday night, the United States and Iran announced a preliminary agreement over Iran’s nuclear program. I didn’t even know until the next morning, and I have been playing catch up ever since.

That said, I have encountered a lot of discussion on social media about the deal. Having spent all those years analyzing the credibility of nuclear agreements, I wanted to make five quick comments about the Iranian deal and such deals in general:

1) Bargaining can work.
A common misconception about bargaining over weapons is that any deal is inherently incredible. The theory is as follows. To buy off a proliferator, the rival needs to offer concessions. But those concessions are hard to retract if the proliferator is not compliant. Thus, the proliferator can take the concessions and build weapons anyway. In turn, because offering concessions has no impact on the proliferator’s decision, the rival should not attempt a bargain.

Although I believed this intuition was true when I began my research project on bargaining over proliferation, it turns out this is wrong. Bargaining over nuclear weapons works. The reason is that a proliferator will ultimately receive some amount of concessions. The rival can just offer most of those concessions off the bat. At that point, the proliferator has no incentive to develop nuclear weapons–if it did, it wouldn’t get much more than it is already getting, but it will have to pay the costs. So bargaining can work.

2) Iran is getting an awful deal (so far).
Broadly, rivals can use one of two nonproliferation strategies. First, they can use “carrots” in the form of the concessions mentioned above. Second, they can use “sticks” like sanctions and preventive war.

Although the announced deal is only preliminary, Iran isn’t getting any carrots. The deal essentially places the United States and Iran at the status quo ex ante: the United States is lifting most of its sanctions (with some oil embargoes remaining), while Iran is agreeing to stricter weapons inspections. As the narrative goes, the “stick” has beaten Iran into submission.

If we are basically back where we started, what was the point of the last ten years of proliferation? One ad hoc story is that Iran is worried about preventive war. But why hasn’t Iran been worried about preventive war in the last ten years? Israel has consistently called for invasion, and Iran has persistently called its bluff. Meanwhile, despite Netanyahu’s desperate pleas, Obama has yet to campaign for a military option. If anything, American reluctance to intervene in Syria has signaled general war exhaustion. So preventive war does not seem to be the answer.

The other ad hoc story is that sanctions are crippling Iran’s economy. But this by itself is unsatisfying–policymakers in Iran must have foreseen that the United States would sanction Iran for noncompliance. Yet Tehran marched forward anyway–the regime must have calculated that the costs of nuclear weapons (both from sanctions and the R&D costs) were worth the end product. One way to resolve this is to assume that the United States had private information on the effectiveness of sanctions–Iran grossly underestimated the effectiveness of sanctions, while the U.S. knew they would work to perfection. If you think that sanctions were wildly more effective than anticipated, then you could reasonably expect the announced deal to be credible, and Iran will forgo proliferation so as to avoid more sanctions.

If you are skeptical that this is the case–and I am–then the United States will need to offer carrots to induce Iran’s compliance. In the absence of credible and effective “stick” options, nonproliferation agreements only work when potential proliferators receive good deals. The announced deal could not be much further from that, as Iran is getting nothing more than what it would have received had it not walked down this road at all. Perhaps these carrots will come in the second stages of negotiations. For now, however, if you think that the sanctions were not sufficiently effective, then this deal will not work until the United States gets out its checkbook.

3) Carrots must be permanent carrots.
If carrots are a part of some eventual grand bargain, they won’t come cheap. Washington won’t just be able to write Iran a one-time check for \$10 billion in aid and expect the problem to go away. Rather, the U.S. will have to keep offering Iran that amount of aid year in and year out. In contrast, if concessions are a one-time gift, Iran has no incentive to maintain the deal going forward. That doesn’t mean that the United States shouldn’t pursue a deal. After all, deals are credible when structured correctly. Just don’t expect a comprehensive agreement to be on the cheap.

Along these same lines, the United States needs to make sure it will credibly give those carrots year in and year out. If Iran expects that a deal will suddenly stop at America’s whimsy–perhaps because of a new, hardline president–the deal will fail.

4) Inspections aren’t pointless.
Hardliners seem to have a mantra that inspections are useless since they can never be all-encompassing. They miss the point. Inspections aren’t always designed to create perfect information. Rather, inspections make it costlier to proliferate, since inspectors force proliferators to develop nuclear weapons via more inefficient means. Greater proliferation costs open up bargaining ranges, reducing the probability of preventive war or further investment in nuclear weapons.

Note, however, that inspections are only an intermediary step. Inspections don’t convince states to completely stop proliferation activities–that is what the carrots are for. Put bluntly, inspections without carrots won’t do much good.

5) War bargaining =/= arms bargaining.
From an IR theorist’s standpoint, it is tempting to use the bargaining model of war as a framework for nuclear negotiations. Yes, there are a number of similarities–bargaining, shadow of war, information issues, commitment problems. But nuclear weapons are not a bargaining object in themselves. No one in Tehran will look at the first Iranian nuclear weapon and think “SHINY!” Rather, nuclear weapons are an inefficient means to an end. Fearon 1995 is a good tool to start with, but we need a larger toolbox to really understand the dynamics of bargaining over proliferation.

Yes, that was a shameless plug for my dissertation.

___________________

The bottom line here is that negotiations aren’t nearly over. The United States will likely have to make real concessions to Iran to induce Tehran to permanently end its program. Anything short of that will lead to more sanctions, preventive war, or nuclear proliferation.