Guest Post by Yon Lupu

Yon Lupu offers this overview of his article that appeared in the October (2013) issue of AJPS entitled “The Informative Power of Treaty Commitment: Using the Spatial Model to Address Selection Effects.”

• Louis Henkin famously observed that “Almost all nations observe almost all principles of international law and almost all of their obligations almost all of the time.”  But do countries adhere to international law because they would have followed its requirements anyway or does the establishment of international law cause countries to change their policies and behaviors?
• Disentangling the correlation between treaty commitment and treaty compliance from possible causal effects of treaty commitment has long been a goal of international relations scholarship.  This article proposes a statistical procedure designed to improve causal inference in this context.  In other words, the procedure will hopefully allow us to better test the causal effects of international law.
• Building on work by Beth Simmons, Dan Hopkins, and Daniel Hill, I proposed to test the effects of treaty commitment by first estimating how likely countries are to join treaties.  We do not observe these probabilities directly, but through their histories of treaty commitment decisions, states reveal significant information regarding which types of treaties they prefer to join and which types of treaties they prefer not to join.  This is analogous to roll-call voting in a legislature: information about the voting preferences of members of Congress is revealed in their voting records.  This information can be analyzed using the W-NOMINATE algorithm created by Poole and Rosenthal in order to estimate the treaty commitment preferences of countries and, in turn, estimate how likely they are to join individual treaties.
•  I applied this procedure to test the effects of three important human rights treaties: the Convention on the Elimination of All Forms of Discrimination against Women (CEDAW), the Convention against Torture (CAT), and the International Covenant on Civil and Political Rights (ICCPR).  Many argue that human rights treaties “don’t matter” and note that any compliance we observe with these agreements is simply the result of leaders refraining from abusing human rights for other reasons.  My results indicate that some of these treaties may result in improvements to human rights practices while others may not.
•  Ratification of CEDAW appears to have led to significant improvements in the political, economic and social rights of women.  By contrast, ratifications of the ICCPR and CAT do not appear to have a significant effect on the extent to which countries engage in violent practices like torture or extrajudicial killings.