Category Archives: Political Science

Bribery and Cartel Violence in Mexico

Mexico has a massive murder problem. 2012 alone saw more than 26,000 homicides in the country, the fourth most of any state in the world. Why?

Drug violence and the interaction between cartels is a major factor. In a new working paper, Paul Zachary (UCSD) and I argue that uncertainty about local leaders has a great impact on that cartel violence. Cartels benefit from using violence to eliminate rivals. Politicians, however, have a vested interest in limiting that violence. This causes tension between cartels and officials, which cartels often attempt to resolve by bribing the officials to look the other way.

Why does uncertainty matter here? Paul and I investigate a model involving two rival cartels—a status quo and a challenger—and a local politician. The cartels want to capture as much of the drug rents as feasible; the local politician wants to minimize violence, but he is willing to look the other way if he receives a large enough bribe. The game begins with the status quo cartel offering a bribe to the politician to minimize enforcement. If the politician rejects, he chooses an amount of effort to exert to reduce the effectiveness of violence, which undermines the status quo cartel’s ability to maintain its drug rents. After, both cartels choose an amount of costly violence, which determines what percentage of the drug rents each receives.

We find that successful bribes lead to higher levels of violence. This is for two reasons. First, and most obviously, additional enforcement intercepts an additional percentage of violence. But there is an important second-order effect as well. The interception of violence functionally increases the marginal cost of violence for the status quo cartel. Consequently, more enforcement not only quashes violence in action but deters some of its production as well.

The above logic leads us to investigate what might lead to bargaining failure during the bribery stage. We show that the status quo cartel’s knowledge of the politician’s level of corruption is key here. When the cartel knows the politician’s minimally sufficient bribe (which is a function of the level of corruption), it can very easily come to terms. But when the cartel can only guess from a wide range of possibilities, it might ultimately offer a bribe that isn’t big enough for the politician to bite. In expectation, this leads to higher levels of enforcement and less subsequent violence.

Our theoretical argument has a noteworthy empirical prediction. Uncertainty leads to less violence, and some work in IR indicates that there is more uncertainty about newer leaders than older leaders. Thus, in Mexico, we would expect municipalities that the same political party has controlled for longer periods to be more violent than municipalities with greater turnover. (In the absence of our argument, this would be odd: the retrospective voting literature would suggest that less violence should correlate with greater tenure, as voters should be rewarding politicians who keep the streets safe.) The data support our theory. Indeed, we estimate that an increase of one year in tenure is associated with roughly one additional murder within a municipality. Although this might not seem like much, with so many municipalities in Mexico, a countrywide increase of one year in tenure matches up with about 2300 more murders. This number is on par with the 2011 murder totals in France, Germany, United Kingdom, Netherlands, and Belgium combined but still only a fraction of the overall number of murders in Mexico in every given year.

Again, you can download the paper here. This is the abstract:

What role do politicians have in bargaining with violent non-state actors to determine the level of violence in their districts? Although some studies address this question in the context of civil war, it is unclear whether their findings generalize to organizations that do not want to overthrow the state. Unlike political actors, criminal groups monopolize markets by using violence to eliminate rivals. In the context of the Mexican Drug War, we argue that increased time in office increases cartels’ knowledge about local political elites’ willingness to accept bribes. With bribes accepted and levels of police enforcement low, cartels endogenously ratchet up levels of violence because its marginal value is greater under these conditions. We formalize our claims with a model and then test its implications with a novel dataset on violent incidents and political tenure in Mexico. We find that each additional year after an official initially takes office is associated with an additional 2,300 violent deaths countrywide.

It’s a working paper, so we’d love your feedback!

My APSA 2014 Presentation: Policy Bargaining and International Conflict

If you are looking for something to do on Friday from 10:15 to noon, head over to the Marriott Jefferson room to see my presentation on Ideology Matters: Policy Bargaining and International Conflict. It is based on a joint project with Peter Bils. Here is the abstract:

Studies of bargaining and war generally focus on two sources of incomplete information: uncertainty about the probability of victory and uncertainty about the costs of fighting. We introduce a third: ideological preferences of a spatial policy. Under these conditions, standard results from the bargaining model of war break down: peace can be inefficient and it may be impossible to avoid war. We then extend the model to allow for cheap talk pre-play communications. Whereas incentives to misrepresent normally render cheap talk irrelevant, here communication can cause peace and ensure that agreements are efficient. Moreover, peace can become more likely when the proposer becomes more uncertain about the opposing state. Our results indicate one major purpose of diplomacy during a crisis is simply to communicate preferences and that such communications can be credible.

If you can’t make it, you can download the paper here, view the slides here, or watch the presentation below:

Multi-Method Research: The Case for Formal Theory

Hein Goemans and I have collaborated on a new research note on formal theory and case studies. Here’s the abstract:

We argue that formal theory and historical case studies, in particular those that use process-tracing, are extremely well-suited companions in multi-method research. To bolster future research employing both case studies and formal theory, we suggest some best practices as well as some (common) pitfalls to avoid.

Since the research note is short by nature, I won’t spend too much extra space discussing it here. You’d be better off skimming or reading the note itself. In essence, though, we argue that formal theory and case studies are natural methodological allies. We also advocate for serious interpretation of a model’s cutpoint into the informal analysis. Manuscripts that combine formal theory with case studies too often spend considerable time developing the model only to ignore it when they begin discussing substance. They should be tied together.

Also, and something that I stress heavily in my book project on nuclear proliferation, we must be very careful in how we interpret those cutpoints. For example, a common fallacy takes the following form: the model says w occurs if x > y + z. The case study then goes to great lengths to prove that y was close to 0 or negative, therefore w should occur. This overlooks the values of x and z, however—even with y equal to 0, the inequality could still fail depending on the relationship between the other parameters. Put differently, and with certain notable exceptions detailed in the research note, we must think about the cutpoints holistically.

Again, you can read the full note here.

Cheap Talk Causes Peace: Policy Bargaining and International Conflict

(Paper here.)

Here are two observations about international diplomacy:

First, crises are often the result of uncertainty about policy preferences. Currently, this is most apparent with the United States, Russia, and Ukraine. It remains unclear exactly how much influence Putin wants over Ukrainian politics. He might have expansionary aims or he may just want moderate control, aware that too much sway over Ukraine will cost Russia too much in subsidies in the long term. In the former case, the United States has reason to worry. In the latter case, the United States can relax.

Second, diplomatic conferences often discuss preferred policies. That is, the parties sit in a room and talk about what they want and what they don’t want. For scholars of crisis bargaining, this is weird. War, after all, is supposed to be the result of uncertainty about power or resolve or credible commitment. These types of discussions are seemingly cheap talk and are therefore supposed to have no effect on bargaining behavior.

In a new working paper, Peter Bils and I help explain these stylized facts. The first observation leads us to set aside the traditional sources of uncertainty–power and resolve–and instead focus on uncertainty over policy preferences on a real line, similar to the spatial model in American politics. The second observation suggests that we should study how cheap talk affects bargaining outcomes in such a world.

Our results are striking and run in contrast to the standard bargaining model of war. Rather than standardize policy preferences on a [0, 1] interval, we allow the winner of a war to endogenously decide what policy to implement afterward. This forces the parties to not only think about how likely they are to win a war and how much it will cost but also consider the quality of their post-conflict outcomes.

Without communication, we find that war may be inevitable–if your opponent’s preferred policy could range from moderate to very extreme, it is impossible to construct an offer to simultaneously appease all types. But if the range possibilities is smaller, peace can be inefficient. This is because the proposer may want to offer an amount that all types are willing to accept. Yet, in doing so, both the proposer and some types of the opponent would be both better off implementing a more moderate policy instead.

We then allow for cheap talk pre-play communication. Normally, cheap talk fails to cause meaningful change because weaker types have incentives to misrepresent; that is, they want to mimic stronger types to receive more generous demands. In some situations, this remains true in our setup. However, cheap talk can occasionally work when the uncertainty is about policy preferences. This is because moderate types sometimes do not want to bluff extremism since doing so would result in an intolerably extremist offer. As a result, where war was previously inevitable and peace was inefficient, peace always works and is efficient as well.

Empirically, this suggests that diplomacy is useful, which helps explain why states spend so much time and effort on it. And despite all of the incentives to lie, cheat, and bluff, those exchanges can sometimes be taken at face value.

Here’s the abstract from the paper:

Studies of bargaining and war generally focus on two sources of incomplete information: uncertainty about the probability of victory and uncertainty about the costs of fighting. We introduce a third: ideological preferences of a spatial policy. Under these conditions, standard results from the bargaining model of war break down: peace can be inefficient and it may be impossible to avoid war. We then extend the model to allow for cheap talk pre-play communications. Whereas incentives to misrepresent normally render cheap talk irrelevant, here communication can cause peace and ensure that agreements are efficient. Moreover, peace can become more likely when the proposer becomes more uncertain about the opposing state. Our results indicate one major purpose of diplomacy during a crisis is simply to communicate preferences and that such communications can be credible.

Sanctions, Uncertainty, and Consolidation of Power

The imposition of economic sanctions is curious. If sanctions have coercive power, powerful sanctions ought to deter rivals from pursuing objectionable policies. On the other hand, if sanctions will be ineffective in a particular case, would-be imposers ought to give up and not lose out on the gains of trade. Why, then, do we see sanctions at all?

In a new working paper from Brad Smith and myself, we argue that asymmetric information about a leader’s consolidation of power plays a critical role in the coercive process. (Edit: I am happy to report that the paper has officially been accepted International Studies Quarterly!) Sanctions ostensibly turn a subset of the selectorate against the current regime. Whether that subset will be pivotal in sparking regime change is critical to determining the effectiveness of sanctions. Because local leaders know their own political predicaments better than foreign adversaries, would-be imposers sometimes have to guess whether sanctions will be worthwhile or not.

Brad and I analyze such a predicament using a formal model. When the potential imposer is sufficiently certain that the target is robust to sanctions, it backs down so as to avoid the economic damage of ineffective sanctions. In contrast, if the imposer believes that the target is vulnerable, weaker opponents sometimes concede the policy issue and sometimes bluff strength. The imposer then sometimes calls potential bluffs (to stop the weaker types from cheating too much) and sometimes backs down (to avoid sanctions a tougher target).

While the outcomes are vastly different, we find an important result regarding the imposer’s quality of information. As the imposer becomes sufficiently certain that its target is weak or strong, the probability of sanctions imposition goes to 0. This is either because the imposer backs down at the beginning (thinking it is facing a tougher type) or because the weaker types have less incentive to bluff toughness. In turn, sanctions are most likely when the imposer is less confident about his opponent’s consolidation of power. This yields a clear testable hypothesis: we should observe fewer sanctions as quality of information increases.

Of course, information (i.e., quality of intelligence estimates) is very difficult to measure. Fortunately, recent works from Scott Wolford and Toby Rider indicate that leader tenure is a useful proxy. Leaders earlier in their careers represent greater unknowns. Over time, publicly observable actions and intelligence gathering improves intelligence estimates. Thus, we expect the likelihood of sanctions to be decreasing in the length of a target’s tenure.

Sure enough, the data support this hypothesis. Moreover, tenure is substantively significant. The plot below shows the predicted probability of sanctions given a crisis as a function of logged leader tenure, holding other observable factors at their medians. A crisis occurring four years into a leader’s term, for example, is 22% less likely to end in sanctions than if the crisis occurred at the beginning.

daysplot

Further, the effect is strongest for autocratic regimes. This fits with the theory. After all, compared to democracies, it is harder to tell who the winning coalition is in an autocracy. Increases in tenure thus generate more information about an autocrat’s vulnerability to sanctions, which in turn more precipitously drops the probability of sanction implementation.

Beyond the theoretical and substantive results, we think a key takeaway is further confirmation of tenure as a proxy for uncertainty. We encourage other scholars to consider using it in empirical models where asymmetric information affects outcomes.

Once again, here’s the paper. The abstract is below.

When do states impose sanctions on their rivals? We develop a formal model of domestic power consolidation, threats, escalation, and imposition of sanctions. With complete information, the target regime’s consolidation of power determines the result—leaders with stable control can weather sanctions and thus deter their imposition, while vulnerable leaders concede the issue. However, when an imposer is uncertain of a foreign leader’s consolidation, vulnerable types have incentive to bluff strength. Foreign powers sometimes respond by imposing sanctions, even though the parties would have resolved the crisis earlier with complete information. We then hypothesize that opponents of newer leaders—particularly in autocracies—are more likely to suffer from this information problem. Employing the Threat and Imposition of Sanctions (TIES) dataset and carefully addressing selection problems common to the sanctions literature, we show that sanctioners are indeed more likely to follow through on threats against such leaders.

New Version of “War Exhaustion and the Credibility of Arms Treaties”

I just updated the manuscript as a standalone paper. Here’s the abstract:

Why do some states agree to arms treaties while others fail to come to terms? I argue that the changing credibility of preventive war is an important determinant of arms treaty stability. If preventive war is never an option, states can reach settlements that both prefer to costly arms construction. However, if preventive war is incredible today but will be credible in the future, a commitment problem results: the state considering investment faces a “window of opportunity” and must build the arms or it will not receive concessions later on. Thus, arms treaties fail under these conditions. I then apply the theoretical findings to the Soviet Union’s decision to build nuclear weapons in 1949. War exhaustion made preventive war incredible for the United States immediately following World War II, but lingering concerns about future preventive action caused Moscow to proliferate.

Download the full paper here.

Interpret Your Cutpoints

Here is a bad research design I see way too frequently.* The author presents a model. The model shows that if sufficient amounts of x exist, then y follows. The author then provides a case study, showing that x existed and y occurred. Done.

Do you see the problem there? I removed “sufficient” as a qualifier for x from one sentence to the next. Unfortunately, by doing so, I have made the case study worthless. In fact, such case studies often undermine the exact point the author was trying to make with the model!

Let me illustrate my point with the following (intentionally ridiculous) example. Consider the standard bargaining model of war. State A and State B are in negotiations. If bargaining breaks down, A prevails militarily and takes the entire good the parties are bargaining over with probability p_A; B prevails with complementary probability, or 1 – p_A. War is costly, however; states pay respective costs c_A and c_B > 0.

That is the standard model. Now let me spice it up. One thing that the model does not consider is the cost of the stationery**, ink, and paper necessary to sign a peaceful agreement. Let’s call that cost s, and let’s suppose (without loss of generality) that state A necessarily pays the stationery costs.

Can the parties reach a peaceful agreement? Well, let x be A’s share of a peaceful settlement. A prefers a settlement if it pays more than war, or x – s > p_A – c_A. We can rewrite this as x > p_A – c_A + s.

Meanwhile, B prefers a settlement if the remainder pays better than war, or 1 – x > 1 – p_A – c_B. This reduces to x < p_A + c_B.

Stringing these inequalities together, mutually preferable peaceful settlements exist if p_A – c_A + s < x < p_A + c_B. In turn, such an x exists if s < c_A + c_B.

Nice! I have found a new rationalist explanation for war! You see, if the costs of stationery exceed the costs of war (or s > c_A + c_B), at least one state would always prefer war to peace. Thus, peace is unsustainable.

Of course, my argument is completely ridiculous–stationery does not cost that much. My theory remains valid, it just lacksĀ empirical plausibility.

And, yet, formal theorists too often fail to substantively interpret their cutpoints in this way. That is, they do not ask if real-life parameters could ever sustain the conditions necessary to lead to the behavior described.

Instead, you will get case studies that look like the following:

I presented a model that shows that the costs of stationery can lead to war. In analyzing the historical record of World War I, it becomes clear that the stationery of the bargained resolution would have been very expensive, as the ball point pen had only been invented 25 years ago and was still prohibitively costly. Thus, World War I started.

Completely ridiculous! And, in fact, the case study demonstrated the opposite of what the author had intended. That is, if you actually analyze the cutpoint, you will see that the cost of stationery was much lower than the costs of war, and thus the cost of stationery (at best) had a negligible causal connection to the conflict.

In sum, please, please interpret your cutpoints. Your model only provides useful insight if its parameters match what occurred in reality. It is not sufficient to say that cost existed; rather, you must show that the cost was sufficiently high (or low) compared to the other parameters of your model.

* This blog post is the result of presentations I observed at ISA and Midwest, though I have seen some published papers like this as well.

** I am resisting the urge to make this an infinite horizon model so I can solve for the stationary MPE of a stationery game.