Amid discussions of trade, territorial security and the diplomatic status of Cuba, arguably the most pressing issue at the recent Summit of the Americas was the lingering problem of drug trafficking.

The narcotics-related violence that has plagued nations like Mexico and Colombia concerns everyone in the Americas, but there's a growing north-south divide in the way countries go about quelling the drug trade.

While Prime Minister Stephen Harper surprised many by conceding that "the current approach is not working," both Canada and the U.S. continue to believe that the problem can only be solved by enforcing prohibition, a tactic experts say has only expanded the black market and increased the power of drug cartels.

But in the last few years, the leaders of countries like Mexico, Guatemala and Brazil have publicly advocated legalizing drugs and are likely to champion that approach at the summit, which starts tonight in Cartagena, Colombia.

"Up until now, it has been heresy for anyone to challenge blanket global drug prohibition," says Donald McPherson, executive director of the Canadian Drug Policy Coalition.

U.S. zero-tolerance policy influenced others

What he's referring to is the U.S. strategy of criminalizing the possession of even small amounts of drugs, imposing harsh jail sentences on users and traffickers and deploying firepower and foreign funds to battle traffickers beyond its borders.

"International drug policy to this point has largely been an extension of American policy," says Eugene Oscapella, a lawyer who teaches drug policy at the University of Ottawa.

America's "war on drugs" — a term coined by U.S. president Richard Nixon in 1971 — has been felt in many corners of Latin America and has included actions and policies that some observers feel were meant to satisfy political aims rather than anti-drug objectives.

The enforcement strategy has included training paramilitary groups in Colombia to fight leftist rebels and using Panamanian strongman Gen. Manuel Noriega to funnel aid to the "contras" in Nicaragua, the guerrilla groups fighting the leftist government of the Sandinista National Liberation Front.

A U.S. Coast Guard stands next to approximately 3,500 pounds of cocaine confiscated from a 35-foot boat near Miami Beach, Florida in March 2012. (Joe Raedle/Getty Images)

America's 40-year anti-drug crusade has reportedly cost trillions of dollars and, according to many critics, accomplished very little.

McPherson says he's seeing a growing willingness among leaders in Latin America to "call a spade a spade: that the War on Drugs has failed, it's killing our people." There is a desire among these leaders to "design a process where we can consider alternatives and bring these substances into a more regulated type of scheme," McPherson said.

A public health problem

Shannon O'Neil, a Latin America expert for the Council on Foreign Relations, feels the legalization debate highlights philosophical differences about the most urgent consequence of drug use.

She says that many Latin American countries put a greater "focus on the public health side of it than building more prisons and treating drug-taking as a criminal problem."

In 2009, Mexico enacted a law that decriminalized possession of minor amounts of drugs, including marijuana, cocaine, heroin, LSD and methamphetamine. While people aren't prosecuted for having small sums of these drugs, they are encouraged to seek treatment.

"The idea there is you don't clog up the system with thousands of users," says O'Neil. "You go for the higher levels up — the dealers, the suppliers and the organized crime members."

Last month, U.S. Vice-President Joseph Biden conducted a two-day swing through Mexico and Honduras, which have first-hand experience of the horrors of the drug trade. Since 2006, more than 50,000 people have died in Mexico in drug-related violence while Honduras, a key point on the Central American drug route, boasts a murder rate roughly 20 times that of the U.S.

The leaders of Mexico, Guatemala, El Salvador and Colombia have all proposed drug decriminalization as a way of damaging the black market and thus reducing the cartels' clout.

During his visit, Biden acknowledged that the debate was "legitimate" but stressed that "there is no possibility the Obama-Biden administration will change its policy on legalization."

Prison industry profits from prohibition

Oscapella believes America's dogged opposition to legalization is largely the result of an entrenched industry connected with prohibition.

Those in favour of legalizing marijuana in the U.S. say that it will put fewer people in prison and allow states to divert those funds to programs like health and education. (Joe Raedle/Getty Images)

"There are many interests within society, many of them powerful interests, that profit from prohibition," says Oscapella, which includes the private prison industry and public and private police forces.

Oscapella cites a recent pitch by the Corrections Corporation of America, the largest operator of prisons in the U.S. The company told 48 U.S. states that it would buy their existing prisons, provided the states could guarantee 90 per cent occupancy.

Although it may not be as brazenly capitalistic, Oscapella says a similar mindset exists in Canada.

"You see it with the current administration in Ottawa, who profit from being tough on drugs," says Oscapella. "They know it doesn't work. Harper's not stupid — he's an economist, he can understand the economics of prohibition, as can many of his MPs.

"But as long as they figure they can gull the public into believing that getting tough on drugs is the right thing to do, they get elected on those things."

Demand still high

One of the few positive outcomes of the war on drugs has been a marked decrease in violent crime in U.S. cities. But the enthusiasm for recreational drugs has, if anything, increased.

After members of the Zetas cartel firebombed a Monterrey casino in August 2011, killing 52 people, Mexican President Felipe Calderon pointed the finger at the U.S.

"The economic power and firepower of the criminal organizations operating in Mexico and Latin America come from this endless demand for drugs in the United States," he said.

The bulk of marijuana, methamphetamine, cocaine and heroin consumed in the U.S. comes from or via Mexico, while the majority of arms used by the Mexican cartels trafficking these drugs comes from the U.S.

Oscapella says that by maintaining prohibitionist policies in the face of unwavering demand, "we export the problem of violence to the producer and transit countries."

While many legalization advocates see the U.S. as intransigent, O'Neil says continued discussion could prod the U.S. to modify its attitude — slightly.

"Drug legalization in the United States is unlikely to happen any time soon, but these debates help with a conceptual turn away from just a law enforcement stance to a public health stance."