According to most of the people running law-enforcement agencies along the U.S./Mexico border, so-called "spillover" violence from Mexico isn't really happening.
Some grandstanding politicians would swear otherwise, but a Government Accountability Office report says officials from 31 of 37 state and local law-enforcement agencies on the border "stated that they have not observed violent crime from Mexico regularly spilling into their counties."
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Really, there's no way to tell for sure -- there's no tracking system for crimes that are attributed to spillover crime, so asking the cops seems to be the best indicator.
"No common federal government definition of such crime exists, and Department of Homeland Security (DHS) and Department of Justice (DOJ) components, including those with a definition, either do not collect data to track spillover crime, or do not maintain such data that can be readily retrieved and analyzed," the report notes.
That seems apparent, as the people we assume to be the law-enforcement heads who claimed spillover violence have varying interpretations of what they're attributing to spillover from Mexico (page 24):
Even Governor Jan Brewer appears to have her own definition of spillover violence.
"As the saying goes, there are lies, damned lies and statistics," she told the New York Times last summer. "Fifty thousand people in Mexico have been murdered. Puerto Peñasco, 60 miles south of our border, just had five people and a police officer killed. That is like part of Arizona, and it is spilling over into our state."
In addition to talking to the cops, the GAO also checked some stats that might indicate spillover violence -- assaults on border agents, violent crimes, and property crimes.
Those crimes decreased, decreased, and decreased, respectively, from 2004 to 2011.
In fact, of the four states sharing the border, Arizona, California, New Mexico, and Texas, only Arizona's border counties have more violent crimes than the non-border counties.
"However, the crime rate decreased in both, with the rate in border counties being 33 percent lower in 2011 than 2004, and the rate in nonborder counties being 22 percent lower," the report says.
"In addition, the FBI reported that its Latin American Southwest Border Threat Section--created to focus on issues specifically related to drug cartels--began in fiscal year 2010 to classify incidents of violent crime with links to Mexico, including kidnappings of American citizens and non-terrorism-related hostage taking occurring in or having a substantial nexus to Mexico or Central and South America," another part of the report reads on page 19. "...None of these cases occurred in the United States."
Still, not everyone's convinced. For example, the GAO cites, "The 2011 Arizona Counter Terrorism Information Center threat assessment stated that the southwest border violence, such as kidnappings and home invasions carried out by Mexican criminal organizations, and gang-related violence, present the most substantial threat to public safety in Arizona.
According to the report, this is from the school of thought that spillover violence "can have effects on the border communities that are not captured in the crime statistics."
You can read the entire report here.