That's not how things are playing out. The MSM has been full of stories about rising levels of violence in Mexican border towns caused by drug lords. These stories always say that the guns fueling the conflict come from the US. They often add the claim that these guns are bought legally at gun shows then smuggled across the border.
A closer look at the stories shows that the gun show story is fiction. The Mexican gangs are using fully automatic weapons and grenades, weapons that are not legally available in the US. The press, which tends to be anti-gun, is dutifully repeating this. Here is an example from MSNBC
"I feel very strongly we have a co-responsibility," Clinton told reporters, adding: "Our insatiable demand for illegal drugs fuels the drug trade. Our inability to prevent weapons from being illegally smuggled across the border to arm these criminals causes the deaths of police officers, soldiers and civilians."
Criminals are outgunning law enforcement officials, she said, referring to guns and military-style equipment such as night-vision goggles and body armor that the cartels are smuggling from the U.S.
"Clearly, what we have been doing has not worked and it is unfair for our incapacity ... to be creating a situation where people are holding the Mexican government and people responsible," she said. "That's not right."
Clinton said she would repeat her acknowledgment as loudly and as often as needed during her two-day visit to Mexico City and the northern city of Monterrey. Officials said her priorities included encouraging the administration of Mexican President Felipe Calderon to increase its battle against rampant corruption by promoting police and judicial reform.
In the 1990s, President Clinton failed to convince the country that we had to ban informal gun purchases through gun shows in order to save ourselves from gun violence. Now President Obama and Secretary of State Clinton are trying to outlaw gun show sales in order to protect the Mexicans from US guns.
Even if Mexican guns were coming from the US, the obvious solution is to close the border to both drugs and guns (and illegal workers). It is the open border that is fueling Mexican drug trade. To his credit, Obama has taken steps to secure the border but this has not slowed Hillary's speeches about American guns coming into Mexico nor Congressional talk about reviving assault weapon legislation.
Ever the opportunists, the Obama administration is using a false premise as an opening for new gun regulations.
3/31/9 Update: The campaign against guns isn't working. Law enforcement personnel testifying before Congress indicated that the Mexican weapons are coming from multiple countries, often bought and shipped to the Mexican army then diverted to the drug lords.