Friends and Neighbors in the Arms Trade

Recently, Syrian rebels (under EU embargo until mid-2013) have relied on weapons smuggled from neighboring states including Iraq, Lebanon, and Turkey (source).

Recently, Syrian rebels (under EU embargo until mid-2013) have relied on weapons smuggled from neighboring states including Iraq, Lebanon, and Turkey (source).  Image from

Why do arms embargoes fail? Despite their frequent use by international organizations like the United Nations and the European Union, arms embargoes suffer from a poor record of success. For half a century now, multilateral arms embargoes have been the primary tool used to fight the proliferation of small arms and light weapons (SALW) to conflict zones and perpetrators of mass violence. These agreements between countries prohibit the sale of weapons to a particular target country (or sometimes a target organization). However, official reviews and academic studies alike tend to conclude that small arms are still making their way to embargoed actors.

Black markets are often cited as a source of this failure. Still, no large-n studies have presented evidence of increased black market activity in the presence of embargoes. To remedy this, I look for evidence of black market activity in records of legal arms trades. The data reveal that arms embargoes are associated with a substantial increase in the value of arms imports into nearby states. Given previous research on the nature of black market arms trade, this seems likely to result from an incentive for neighboring states to import more weapons that will then be transferred illegally to the embargoed state.

Black market arms transfers are difficult to study. Most of what we know about illicit arms transfers comes from those cases where somebody has made a mistake and the illicit activity has been uncovered. Apart from those few select cases, reliable data on actual illegal arms transfers is unavailable. Nonetheless, the illicit arms trade is big business, measuring roughly one billion USD per year.

Embargoed states and their neighbors.

Embargoed states and their neighbors. Embargoes based on data from Erickson (2013), Journal of Peace Research.

Black markets are of particular concern in situations where the legal supply of weapons is low but the demand is high. These circumstances often apply to criminal organizations, rebel groups, and embargoed states. While these illicit trades are difficult to collect data on systematically, most of the weapons involved begin as legally-traded arms. They are traded legally and then diverted from their authorized recipients. Arms embargoes provide an interesting case for the study of illicit arms. Those countries that border embargoed states can take advantage of their shared border to traffic illegal arms to the embargoed neighbor without fear of discovery by a third party. Therefore, if embargoed countries circumvent those embargoes by purchasing arms illicitly, we should expect to see an increase in the arms imported to their neighbors.

I have used data on multilateral arms embargos and legal arms transfers to test this proposition. Statistical models reveal that arms embargoes are indeed associated with greater levels of weapons imports in nearby countries. In fact, the predicted increase is substantial: those countries that border embargoed countries are estimated to import 38% more arms than they would have had they not been neighboring an embargoed country (measured in value, constant 2000 USD). This can translate into hundreds of thousands or even millions of dollars worth of additional weapons. Furthermore, this result takes into account both domestic and international conflict as well as other predictors of arms imports like the overall level of arms imports to the region, government type, and GDP per capita. On the other hand, this analysis indicates that arms embargoes are indeed effective at stemming the flow of legal arms into embargoed countries. Countries targeted by an embargo are predicted to import, on average, 63% fewer arms than they would otherwise.

Predicted levels of arms imports for a hypothetical median state bordering an embargoed state and not bordering an embargoed state.  Fixed effect uncertainty included.  Based on 100,000 simulations.

Predicted levels of arms imports for a hypothetical median state bordering an embargoed state and not bordering an embargoed state. Fixed effect uncertainty included. Based on 100,000 simulations.

Arms embargoes appear to effectively decrease the legal, or recorded, sale of arms to target states. However, this effect is accompanied by a significant increase in the level of arms imported to the surrounding region. Absent other possible explanations, it seems likely that many of these arms are destined for the embargoed country. Effective arms control measures must account for the regional conditions that may undermine nonproliferation efforts.

  1. Very interesting post, I have a question though. Perhaps I didn´t understand well the visualization or my search wasn’t thorough enough, but I wasn’t able to find an instance in which Chile was under arms embargo in the 00’s.

    • Hi Hernan, thank you for pointing this out. I have used two different data sources on arms embargoes for all of my models – one from the Stockholm International Peace Research Institute and the other from a paper published by Jennifer Erickson in the Journal of Peace Research (2013). While the two datasets generally agree, there are a few discrepancies and Chile is one of those. Indeed, I believe SIPRI was the foundation for the larger dataset found in the Erickson (2013) article. These maps in particular were created with Erickson’s data which codes an Austrian arms embargo towards Chile for the years 1995 through 2004. I agree that this is strange and will look into it.

  2. Hi, this post is very interesting but could you be more specific about the data used? Are they from the Stockholm International Peace Research Institute (SIPRI)? Thanks.

    • Hi Elio, the data come from both the SIPRI database you mentioned and from the replication data for a paper published by Jennifer Erickson in the Journal of Peace Research (2013). The results of this paper are robust to the data sources.

  3. Hi Ben,

    Good work and thanks for sharing it with us.

    While there is anecdotal evidence for this pattern (ie. Saudi Arabia buying small arms to give to rebels in Syria) I don’t think I find the large-scale evidence very convincing in its current form. I can imagine that most embargoes target civil war countries. But it is not surprising that neighbors of a civil war state buy more guns; civil wars induce fear of war-diffusion in neighboring countries which would make them buy more guns to defend themselves. I think this mechanism would predict what you find for neighbors of embargoed countries as well as the neighbors of any country in civil war.

    Perhaps you could test whether the neighbors of an embargoed state buy even “more” guns than the neighbors of any civil war state. The model I have in mind is this:

    Arms = Civil_War_Neighbor + Arms_Embargoe + (Civil_War_Neighbor * Arms_Embargoe) + Controls

    Finally, here is an interesting paper on illegal arms trade:


    • Hi kerimcan81,

      Sorry for the delay in getting to you and thank you for your feedback and paper recommendation! I’m not sure that an interaction is the correct approach – would states that fear the diffusion of civil war also fuel that civil war by trafficking weapons to belligerents? (Though you’re right that it is possible that states may fear contagion but profiteers within those states will nonetheless traffic weapons across the border.) Instead, controlling for a neighboring civil war without an interaction term should help us to account for the effect of contagion fears. While many embargoed states experience a civil war for at least some of the years for which they are embargoed (but certainly not all), many civil war states are never embargoed. The correlation between civil war country years and embargoed country years in this dataset is 0.16 and then decreases depending on coding choices.

      Thank you for your feedback!

      • Hi, I think you’re right. A simple “civil war neighbor” dummy should be enough.

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