Figures from last week's Star Tribune series about Minnesota-to-Mexico gun smuggling were jaw-dropping: An estimated 2,000 firearms cross the border illegally from the United States into Mexico every day. Gunrunners can make $500 to $1,000 per gun by selling them to Mexican drug thugs. And though the U.S. government has provided $1.6 billion in aid to Mexico to help shore up the borders, that's a pittance against the $30 billion drug trade.

But the most stunning statistic of all is 23,000 -- the number of Mexican murders directly linked to the drug trade since 2006. That killing was done with firearms from the United States, including Minnesota.

All that death underscores the urgent need to get at the core of the problem -- America's insatiable demand for illegal drugs.

In a chilling four-part series, Star Tribune reporter Jim Walsh comprehensively documented what authorities call the "iron pipeline'' through the story of a Minnesota gunrunner who got caught.

To his Medford, Minn., neighbors and friends, Paul Giovanni de la Rosa was a father of four and a soccer dad who was sometimes "away on business.'' Turns out that business was buying guns legally in Owatonna and Albert Lea, then smuggling them across the border to sell to drug cartels.

The U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) says that 90 percent of the guns recovered at Mexican drug-related crime scenes and successfully traced are from the United States.

ATF agents caught up with de la Rosa late last year after following his gun-buying patterns between 2007 and 2009. He was arrested at a Texas border town in November, driving a minivan that had 14 guns and 200 rounds of ammunition hidden in a piece of furniture.

Some might suggest that the pipeline could be closed by adopting tougher gun laws. But in this case the current system worked because federal law requires gun sellers to record who buys weapons and how many. One improvement would be to share that cross-jurisdictional information faster. One of the weapons de la Rosa bought in 2007 was recovered two months later at a Mexican crime scene, but he was not arrested until more than a year later.

Certainly, strong law enforcement matters. However, even if the U.S. and Mexican governments quadruple their efforts, the porous border, high demand and big money involved could eclipse police capabilities.

Therefore, prevention, treatment and other demand-reducing efforts would have the greatest impact on reducing drug crimes. Federal officials say that marijuana makes up the lion's share of illegal drugs smuggled north from Mexico. So if thousands of Americans could kick the habit, whether recreational or chronic, financial incentives for gangs and drug cartels would dry up -- and so would the related killing.

Remember, every time drug money changes hands on a local rural road, a metro street, a college campus or high school parking lot, some of that cash buys guns to kill people in another nation. Our national appetite for marijuana, cocaine and meth from Mexico makes buyers and sellers accessories to assassination.

Minneapolis Mayor R.T. Rybak has linked drug buys to this year's troubling increased murder rate. He said that those who come to Minneapolis to buy drugs might as well be buying bullets to kill people. That those purchases also cause tens of thousands more deaths in another nation should help refocus efforts to reduce demand here at home.