When you cross on foot over the bridge that joins El Paso, Texas - safest city of its size in the United States - with Ciudad Juárez - murder capital of the world, you need no money, no identification, and your bag is unlikely to be checked. And you'll see a small sign reminding you that it is illegal to possess guns in Mexico. 

Every day, according to a study by Magda Coss, two thousand firearms pass from the United States into Mexico. In Phoenix and Houston, or at most of the 6,600 gun dealers near the Mexican border, if you don't have a criminal record, it is legal to walk in, buy 10 or 20 AK-47s or AR-15s, or Five-seveN guns designed to penetratearmor and bullet-proof vests, and walk out. 

The Pentagon, for its part, is providing equipment and training to the Mexican police and army, in a strategy that tracks back and forth between the two as favored clients. Sometimes Mexican policemen are direct victims of organized crime seeking to control the state's actions; sometimes policemen act in concert with organized crime, as when Federal Police have stopped Central American migrants seeking to reach the United States and turned them over to organizations that systematically take the cash they've saved to pay to cross the border, and in many cases then kill the migrants. Sometimes policemen kill criminals or ordinary people, and attribute the crime to the Zetas or Sinaloa cartel.

Either way, the guns are coming from the United States, some from public taxpayer funds, some from private dealers. And Mexican gunmen - of the state or not - are in an arms race for ever-more powerful weapons. 

Sometimes U.S. public and private interests combine to sell weapons, as in Operation Fast and Furious, run out of the Phoenix office of the Bureau of Alcohol, Tobacco and Firearms in 2009 and 2010, by which dealers sold more than 2,000 weapons to "straw buyers," individuals who can legally buy weapons, but who illegally turn them over to others. ATF allowed the weapons to "walk", reportedly in an effort to identify higher-ups in gun trafficking organizations but, once out of the stores, it is practically impossible to control them. Hundreds of the guns have turned up at crime scenes in both the U.S. and Mexico, including at the killing of a Border Patrol agent in January. 

The operation obeyed the callous dehumanized logic of police who believe that, as one ATF official said to an officer who objected, "you have to break eggs to make an omelette." But it also responded to the free market religion by which guns are treated like any other object in the marketplace. To prosecute gun traffickers, ATF usually must bust marginal figures on paper violations, and district attorneys are often reluctant to prosecute such low-level crime. 

Meanwhile, Lone Wolf Trading in Glendale, AZ made good money on the sales. The National Rifle Association is having a hey-day with Fast and Furious, pummeling ATF to weaken its enforcement capacity even further, while Rep. Darrell Issa employs it to go after Attorney General Eric Holder. Mexicans in Ciudad Juárez I talk with read the scandal as further evidence that the United States government is trying to kill them. The treatment of immigrants detained by U.S. personnel along the border, in what No More Deaths calls "a culture of cruelty," shows that these Mexicans perceive something real, whether it's conscious or unconscious.

So who will stop the river of death into Mexico? Will the Mexican government stop it? Will Washington? Who? and when will they do it?

Media, military and politicians speak of "spillover violence," referring to the fear that the murder taking place in Mexico will visit U.S. communities. In fact, spillover violence is going in the other direction. It is the United States that supplies the guns, the military strategy, the money from drug sales, the tradepolicy that depopulates rural agriculture through subsidized imports, and runs an immigration policy that uses and then dumps people. 

In the last two years, churches in Philadelphia, Harrisonburg, Baltimore and other cities decided to confront gun dealers whose products were a problem in crimes committed in their communities. Calling themselves Heeding God's Call, they asked the dealers to commit to a ten-point code of conduct that can prevent straw purchasing of guns. If the dealer says no, they escalate to vigils, media outreach, talking with local government. Several groups, including Heeding God's Call, Fellowship of Reconciliation, Presbyterian Peace Fellowship, and the Brady Campaign to Prevent Gun Violence, are putting together a Borderlands Heeding God's Call to address gun trafficking from border areas. We're seeking a local part-time organizer to jump start this project; if interested, apply by October 31. 

To urge President Obama to take action against gun smuggling to Mexico, sign the petition at www.alianzacivica.org.mx/altoalasarmas

The occupy movement shifts the subject of action for justice from them to us: it is we occupy the plaza. And so it must be we who act to detain the tools designed only to kill and intimidate people. 

For more information or to get involved in Borderlands Heeding God's Call, contact John Lindsay-Poland, johnlp@forusa.org. 

[The author is Research and Advocacy Director of the Fellowship of Reconciliation.]