What is the best way to deal with drugs? Criminalizing drug users or treating them as patients? Sticking to a strict prohibitionist stance or experimenting with alternative forms of regulation and prevention?

Latin America is talking about drugs like never before. The taboo that has long prevented open debate about drug policies has been broken -- thanks to a steadily deteriorating situation on the ground and the courageous stand taken by presidents Juan Manuel Santos of Colombia, Otto Perez Molina of Guatemala and Laura Chinchilla of Costa Rica.

The facts speak for themselves. The foundations of the U.S.-led war on drugs -- eradication of production, interdiction of traffic, and criminalization of consumption -- have not succeeded and never will. When there is established demand for a consumer product, there will be a supply. The only beneficiaries of prohibition are the drug cartels.

Forty years of strenuous efforts have failed to reduce the production and consumption of illicit drugs. Worse, in Mexico and Central America, prohibition-related violence and corruption have become a major threat to public safety and the stability of democratic institutions.

In light of the disastrous consequences of the war on drugs, we took the initiative four years ago to convene a Latin American Commission on Drugs and Democracy -- and, more recently, a Global Commission on Drug Policy. Our core message was clear: The war on drugs has failed, with devastating consequences for individuals and societies throughout the Americas.

Our commissions presented two key recommendations. The first was to end -- as soon as possible -- the criminalization and stigmatization of people who use drugs but who do no harm to others. People struggling with drug abuse or addiction may indeed harm themselves and their families, but criminalization and social marginalization are not going to help them.

Drug abuse and addiction are public health problems. The most effective response, then, is to provide treatment and health services to all who need them. The criminalization of drug use is the primary obstacle to treatment and rehabilitation.

Argentina, Brazil, Colombia, Ecuador, Mexico and Uruguay have already passed laws decriminalizing drug possession for personal consumption. However, given that the legal distinctions between "possession" and "trafficking" are unclear, the law often leads to police corruption and outright discrimination against the poor.

The primary objective of drug control policies should be protecting the young, seeking by all means to prevent drug abuse and addiction. This requires increased investments in prevention, treatment and social reintegration. Only such a comprehensive approach can be effective in reducing drug use.

The full enforcement power of the state and the social and cultural pressure of society should be aimed at a relentless fight against organized crime -- rather than persecuting people in need of treatment.

Our second core recommendation -- which is more complex but just as important for ensuring peace and public safety -- is to encourage experimentation with different models of legal regulation of drugs, such as marijuana, in similar ways to what is already done with tobacco and alcohol.

Research has consistently demonstrated that marijuana is a less harmful drug than tobacco or alcohol. Regulation is not the same as legalization. This is a critical point. Regulation is a necessary step to create the conditions for a society to establish all kinds of restrictions and limitations on the production, trade, advertising and consumption of a given substance to deglamorize, discourage and control its use.

The stunning reduction in the consumption of tobacco in the Americas shows that prevention and regulation are more efficient than prohibition and punishment.

Regulation cuts the link between traffickers and consumers. It is this link that enables traffickers to impel people to use ever more harmful drugs. Since marijuana is by far the most widely consumed illicit drug in the world, regulation would also significantly reduce the vast resources -- and thus the vast power and influence -- generated by organized crime in the illegal drug markets..

We congratulate the presidents of Colombia, Guatemala and Costa Rica for having the courage to put different options on the table that would undermine the power of organized crime and safeguard the health and security of their citizens.

For the first time, drug policy will be on the agenda at the Summit of the Americas, which will take place in Cartagena de las lndias, Colombia, on April 14-15. It is unlikely that the heads of state will reach a consensus about such a complex and controversial issue. At this point, what is most needed is a serious and rigorous debate, enabling each country to develop its own position and to adopt more appropriate solutions that take their history and culture into account.

Latin America's experiences in fighting drug traffic, the successful examples set by some European countries in reducing the individual and societal harms of drug misuse, the experimentation of several U.S. states with the medical uses of marijuana, the engagement of the business sector and the scientific community, and the profound wish of the young to live in peace, all point toward more balanced, humane and efficient drug policies.

A paradigm shift, combining repression of the violent drug trade with increased investments in treatment and prevention, would be the best contribution that Latin America -- a region that has suffered so much under drug prohibition -- could make to global reform of drug policies.

Written by Cesar Gaviria, former president of Colombia and member of the Global Commission on Drug Policy; Ernesto Zedillo, former president of Mexico and member of the Global Commission on Drug Policy; and Fernando Henrique Cardoso, former president of Brazil and chair of the Global Commission on Drug Policy