The market for illicit drugs represents the world's largest criminal commodity business. With an estimated annual turnover of up to $US652 billion ($921bn) — about a third the size of the global oil market — it is controlled by criminals who care little for others' health, rights and safety.
Around the world, drug-related deaths have been surging, rising from 183,500 in 2011 to about 450,000 in 2015 — an increase of 145 per cent.
Meanwhile, more than $US100bn continues to be spent every year in a futile attempt to eradicate the illegal-drugs market.
Over 50 years, many countries have even gone so far as to militarise their response. But while some drug cartels have been dismantled, some kingpins brought to justice, and the area under cultivation for cannabis, coca and poppy reduced, these successes have proved only temporary.
Worse, in many cases the problem has simply been foisted on to other countries, causing a "balloon effect".
For instance, after the early 2000s, coca production declined in Colombia and rose in Peru, only to double back to Colombia in more recent years. Because drug traffickers can adapt and change, progress is always reversible.
The human costs have been nothing short of shocking. According to the National Institute of Statistics and Geography, there were more than 250,000 recorded homicides in Mexico between 2006 and 2017. In The Philippines, there have been as many as 20,000 extrajudicial killings since President Rodrigo Duterte assumed office in 2016.
And in Colombia, many political leaders, police officers, soldiers, judges and prosecutors have been murdered while coca farmers — mostly poor smallholders — have been caught in the crossfire between the army, paramilitary groups, insurgents and gangs.
Sadly, this level of violence should come as no surprise. When drugs are banned they are pushed into illegal markets where physical force, intimidation, discrimination and corruption take the place of state-based regulation.
Moreover, prohibition exacerbates the health and social harms associated with drugs by contributing to epidemics of HIV and hepatitis C, overdose deaths, prison overcrowding, stigma and discrimination, poverty and the weakening of institutions.
It is time for the world to change its approach. The use of psychoactive substances is risky behaviour and managing such risks is a function of government.
That is why the Global Commission on Drug Policy, in its report Regulation: The Responsible Control of Drugs, recommends governments legalise and regulate all presently illegal drugs.
Legalisation is often portrayed inaccurately as an intervention by the state to promote drug use. But what it really means is authorities acting in the public interest providing a legal framework for the production, distribution and sale of drugs for adult consumption, with appropriate consideration given to the harms associated with each particular substance.
It is a policy that specifically addresses the realities of drug use and the presence of drug markets.
As with all regulation, reforms should be implemented incrementally and guided by evidence of what works and what does not.
Different drugs will naturally require different levels of regulation depending on their relative risks - and approaches will vary.
Where cannabis might be sold in licensed retail stores, pharmaceutical-grade heroin could be made available with a prescription to people who are dependent and for whom other addiction treatments have not worked.
Neither policymakers nor voters can hide behind the argument that people who use drugs deserve to be treated differently because they have chosen to engage in potentially harmful activity.
Putting aside the fact drug dependency tends to override one's capacity to make such choices freely, we all engage in risky, harmful behaviours, from smoking cigarettes to consuming alcohol, trans fats, processed sugar and so forth.
Fortunately, we already know how to manage risky behaviours and potentially dangerous products, not just from the legal cannabis markets emerging across the Americas, but also from the successes and failures of food safety, alcohol and tobacco control.
The lesson from those over-commercialised legal markets is we need to place appropriate controls on marketing practices and curtail incentives for commercial enterprises to encourage harmful consumption in pursuit of profits.
We also need more prevention and monitoring programs, which would be the case with or without legalisation. Experiences with alternative models also may help guide the transition from criminal to regulated drug production and use when they are implemented alongside sustainable socio-economic development policies.
Thailand, for example, has phased out opium by creating other economic opportunities for farmers. And Bolivia and Turkey have introduced regulated coca and poppy cultivation to push out illegal operations.
By calling for legalisation, we are not surrendering to the problems posed by drugs.
Rather, we are advocating a more effective, lasting and humane solution. Though regulation is not a panacea for all drug-related problems, it is the best hope we have for building a healthier, safer and more just world.
The choice is simple. We can hand control to governments or to criminal organisations. There is no third way.
Juan Manuel Santos is a former president of Colombia, Nobel Peace Prize laureate and a member of the Global Commission on Drug Policy. Ernesto Zedillo is a former president of Mexico and GCDP member. Ruth Dreifuss, a former president of Switzerland, chairs the GCDP.