Mexico ends 2010 with 15,000 illicit drug-related murders for the year—a record for the Calderon administration that began its term four years ago by declaring an all-out war on drug trafficking. Drug war violence skyrocketed since Calderon took office, claiming more than 30,000 lives. Though it is an unwinnable war whose consequences also include the rise of corruption and the weakening of the institutions of civil society, it is being used by drug warriors and skeptics alike to push for pet projects ranging from increased development aid to more military cooperation.

A recent example comes from the Washington Post this week. It editorialized in favor of an Obama administration plan to stem the flow of arms to Mexico, and it ran a story the same day citing the claim that 90 percent of guns in Mexico’s drug war come from the United States (though the Post also noted that the Mexican and U.S. governments refuse to release the results of their weapons traces). My colleague David Rittgers notes here that the proposed gun regulation is unlawful and here he has explained that a more realistic figure for guns of U.S. provenance is about 17 percent. In a Cato bulletin earlier this year, former Mexican foreign minister Jorge Castañeda calculated a similar figure and explained why attempts at controlling the trade in U.S. arms are a waste of time:

In fact, we only know with certainty that about 18 percent of guns come from the United States, according to Mexican and U.S. sources. The rest is surely coming from Central America, countries of the former Soviet Union, and beyond. And as countries as diverse as Brazil, Paraguay, Somalia, and Sudan attest — all countries with a higher arms per capita than Mexico — you don’t need a border with the United States to gain easy access to guns. Nevertheless, the possibilities of really limiting the sales of weapons in the United States is not imminent, to put it mildly. Moreover, asking the United States to stop arms trafficking from north to south is like asking Mexico to control its border from south to north, whether it is for drugs, people, or anything else. It’s not going to happen.