President Obama announced a new push to pass legislation limiting access to deadly weapons last week, adding, "I will put everything I’ve got into this." The proposal encompasses 23 executive orders, three of which Obama has already signed and went into effect immediately: an end to the moratorium on federal research related to gun violence, a mandate for federal agencies to recover and trace weapons encountered over the course of their investigations, and a mandate to comply with a 2007 act that requires agencies to update a federal database regarding the mental health of individuals.

He also proposed various legislative changes: a reinstatement of the assault weapons ban that was in effect from 1994 to 2004, a ban on magazines that contain more than 10 bullets, mandatory criminal background checks for sales at gun shows, a crackdwn on the straw buyers who purchase guns for Mexican gangs, and a prohibition on armor-piercing rounds.

While the increased interest in gun control from the White House stems largely from American tragedies like the Newtown, Conn., mass shooting in December, Obama’s pledges also address a perennial concern of Mexican policy makers. While US officials have often acknowledged their country’s role as a driver of the insecurity in Mexico, this is the first time that they have backed up the rhetoric with attempts to significantly alter domestic policy.

The belief behind the Mexican complaints is that the easy purchase of firearms in the US is a major driver of Mexican violence. More specifically, as former President Calderon argued in an appearance before Congress in 2010, the 2004 expiration of the assault weapons ban has flooded Mexico with AR-15s and other weapons capable of mass mayhem. In the hands of groups like the Zetas, those guns have killed tens of thousands of people in Mexico and sparked a doubling of the murder rate under Calderon.

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While the exact role of US guns in Mexican violence remains a matter of passionate debate, there is certainly evidence to support the complaints. Between 2007 and 2011, Mexico sent roughly 99,000 guns to the US for tracing; the ATF reported that 70 percent, or 68,000, were purchased in the US. Reports of AR-15s being used in Mexican crimes are commonplace, and arrested criminals have discussed their reliance on the US as a source of guns.

More detailed analysis supports the broader conclusions hinted at above. In 2010, Diego Valle-Jones, a specialist in statistical analysis, took a long look at the impact of the assault weapons ban in Nuevo Laredo and Tamaulipas, concluding that "the expiration of the Assault Weapon Ban contributed to the violence in Nuevo Laredo with possible spillover effects in Nuevo Leon."

However, that doesn’t mean Obama’s announcement will reverse the tide of violence. The most obvious obstacle is political: Obama’s announcement won headlines around the country, but his proposal remains a long way from approval, and he faces dogged opposition from the NRA and the group’s Congressional allies. The shooting at Sandy Hook may indeed prove a sea change in the way the US views gun control, but it’s certainly not a foregone conclusion, and it’s worth noting that gun rights advocates have had the better of the debate for close to 20 years.

Moreover, even conceding the importance of the US gun market to the recent wave of killings in Mexico (a finding that other studies have pushed back against), the imposition of the new controls proposed by Obama doesn’t mean that Mexico will experience a corresponding pacification. Unfortunately, the US gun trade is not a condition for Mexican violence, but rather an enabler of it, and a replaceable one at that. To take but one example, the persistent violence in Venezuela demonstrates that access to American gun shops is not a requirement for jolts of criminal bloodshed. Furthermore, Mexico’s foremost criminal groups are sufficiently wealthy and internationally connected that they surely have contacts among international arms dealers; for groups like the Sinaloa Cartel, if it’s not AR-15s from Arizona, it’ll be AK-47s from Azerbaijan.

What increased controls and an assault weapons ban would likely do is raise the cost of black market firearms, so that some smaller gangs might be forced to abandon the use of guns. Since smaller gangs have been a substantial driver of violence, this alone would make the move worthwhile for Mexico. But it would be a largely marginal improvement, and it is wrong to expect a radically new landscape in Mexico on the basis of Obama’s declaration.