One of the most-debated issues about the orgy of drug-related violence in Mexico is whether the turmoil is confined to that country or is having a significant impact on the United States. The conventional wisdom is that although tensions have risen along the U.S.-Mexico border over the past five or six years, the actual impact of our southern neighbor’s carnage on communities in the United States has been minimal. Ioan Grillo, who has reported on developments in Mexico for more than a decade, concedes that Mexican cartels operate throughout the United States, but he insists “there has been no major spillover of violence from Mexico to its northern neighbor. As of 2011, after five years of cartel devastation south of the Rio Grande, the war simply hasn’t crossed the border.”

Those who contend that the specter of Mexican drug cartels terrorizing the American southwest is merely a hysterical myth have some credible evidence on their side. Violent-crime rates in such cities as Tucson, Laredo, San Diego and El Paso have not spiked, despite the pervasive killings on the other side of the border. FBI statistics have consistently shown low homicide rates in El Paso, Tucson and most other southwestern cities.

New York Times writer Andrew Rice, who spent weeks in 2011 studying the effect of the horrific drug violence in Juárez on El Paso (just across the border), concludes that “spillover was notable for its scarcity.” He notes further that while Juárez suffered more than three thousand homicides in 2010, El Paso—a city of some six hundred thousand people—had an astonishingly low total of five. Matters have deteriorated just slightly over the past year.

But there are a growing number of unsettling incidents. In February of this year, a bullet from a gun battle between two drug gangs in Ciudad Juárez struck a mother across the border pushing a baby stroller in downtown El Paso. In May, a San Diego jury convicted two men in a gruesome killing linked to a breakaway faction of the Tijuana-based Arellano-Felix cartel. The men had executed two rivals and disposed of their bodies by dissolving them in acid. The convicted defendants were the first of seventeen accused assassins to go on trial for cases involving nine victims.

Paul Babeu, the sheriff of Pinal County, has long been worried about the increasingly brazen drug-cartel presence in his county and other portions of southern Arizona. In August 2010, when the federal government posted signs along a sixty-mile stretch of Interstate 8 between Casa Grande and Gila Bend, Arizona, warning motorists that they were entering an “active drug and human smuggling area” where they might encounter “armed criminals and smuggling vehicles traveling at high rates of speed,” Babeu went even further than the federal warning signs. He contended that “Mexican drug cartels literally do control parts of Arizona.”

Homicide rates are not the only measure of whether there has been a spillover effect from Mexico’s drug violence. There is also the matter of intimidation. An incident in 2011 illustrates that problem; farmhands in the Rio Grande valley near the small town of La Joya, Texas, were burning stalks of sugarcane for harvest when four masked men on all-terrain vehicles approached them. The armed men surrounded the crew and ordered them to leave the area. Dale Murden, the farmer who employed the crew, said he had no doubt that the masked men were drug traffickers. “They hide stuff in there,” Murden said, referring to the dense fields of sugarcane, and try to intimidate anyone who gets too close.

The incident on his ranch occurred just two weeks after a Hidalgo County, Texas, employee was similarly threatened by masked men and ordered to stop clearing brush along a small river near the border. In early March, men in a pickup truck fired shots at a foreman on a ranch adjacent to property owned by country-music star George Strait.

Texas ranchers and farmers—as well as their counterparts in New Mexico and Arizona—contend that episodes similar to the one Murden’s workers experienced are growing more and more frequent. One farmer, Joe Aguilar, told state officials that he quit farming because of the escalating risk, saying “either you move on, or it’s dangerous for your family.”

The sense of uneasiness among farmers and ranchers in the borderlands is perhaps eclipsed in some Mexican-American communities along the border. People in Fort Hancock, Texas, and other towns along the border are clearly feeling jittery. As Associated Press correspondent Paul Weber reported from Fort Hancock: “When black SUVs trail school buses around here, no one dismisses it as routine traffic. And when three tough-looking Mexican men pace around the high school gym during a basketball game, no one assumes they’re just fans. . . . Mexican families fleeing the violence have moved here or just sent their children, and authorities and residents says gangsters have followed them across the Rio Grande” in a campaign of intimidation.

One high-school student, when picked up for truancy, told a judge he was too scared to go back to class because he had witnessed a murder in Mexico. In Fabens, Texas, fliers were circulated to faculty members asking them to watch for a gunman wanted for four killings in Ciudad Juárez. The suspect was the father of two boys at the Fabens middle school. Texas authorities are increasingly worried that the drug violence will pursue Mexican refugees who have taken up residence in communities along the border. Local police forces have even taken to escorting school buses in some of the high-risk areas.

Mexico’s killing spree has not yet engulfed U.S. communities. Nevertheless, there are some troubling signs. Security worries among ranchers along the border and among Mexican refugees and their relatives in the southwestern United States could be the canary in the coal mine regarding the spillage of Mexico’s problems across the border. Those vulnerable portions of the population would logically be the first to feel the effects. The possibility of spillover can no longer be ignored. The danger needs to be taken seriously.

Ted Galen Carpenter, senior fellow for defense and foreign policy studies at the Cato Institute, is the author of eight books on international affairs, including The National Interest.

Image: quinn.anya