Montevideo, Uruguay - When Uruguay recently became the first country in the world to legalise and regulate the production, distribution and sale of marijuana, it was a long-time dream realised for marijuana activist Juan Vaz.

But it also came with a lot of work and campaigning. Vaz, a co-founder of the Uruguayan Association of Cannabis Studies, is one of the most visible faces associated with the marijuana legislation effort in the country.

He has long advocated for legalisation, and spent time in prison for growing the plant. He says that experience was life-changing and convinced him to fight for legalisation so that none of his fellow cannabis users would suffer the same fate.

By some estimates, 120,000 marijuana consumers in Uruguay will now be able to plant or buy the weed without penalty. According to the Uruguayan Observatory on Drugs, a governmental organisation, the sale of marijuana on the black market currently dominates the illegal drug trade in the country, with estimated sales of $20m annually.

The new law allows consumers to grow up to six female cannabis plants at home, join membership clubs with a 99-maijuana plant limit, and purchase 40 grams of marijuana a month for recreational use. Only Uruguayans or residents of the country will benefit from the measure. The law excludes tourists in an attempt to prevent Uruguay from becoming a "marijuana paradise" .

Marijuana use has been legal in Uruguay since 1974, but buying, selling and planting the drug was not allowed. The new legislation closes that gap, and also goes several steps further by regulating the use of cannabis for medical, scientific or industrial purposes.

The Uruguayan state will control the planting, distribution and consumption of the drug. It will issue licenses to institutions that want to be involved in the production, distribution or selling of cannabis or in the hemp industry that has textile, cosmetic and food applications.

The government will be competing with black-market product, but most experts predict the government's blend will be cheaper and higher-quality than that sold illegally. The country's National Drug Council suggested that the initial price for the cannabis could be set at $1 per gram, and said the product could possibly become available by the middle of next year.

"I would say this [legislation] is the most advanced in the world," said Hannah Hetzer, policy manager for the Americas at the Drug Policy Alliance. Hetzer has been advising the Uruguayan government and sharing examples developed at the local and state level in other parts of the world including the US, where marijuana's recreational use is legal in two states, Colorado and Washington, and allowed for medicinal purposes in many other states.

But many in Uruguay are unhappy about the legislation. In a poll taken earlier this year by Instituto Moris, two-thirds of Uruguayans opposed the measure. Ignacio Zuasnabar, the head of the polling firm, said opposition stemmed from fears that the law could open the door to people who use cannibus moving on to using harder drugs, and that it could cause an increase of crime due to an increase in drug use. Many in the medical field have raised concerns and warned of the risks of marijuana use, especially among teenagers and children.

There is also criticism and concern over the country being the "first" to test this unchartered territory. "Neither our government nor the rest of the world should experiment on Uruguayans," argued Alfredo Solari of the opposition Colorado Party during Senate debate of the measure.

Uruguayan President Jose Mujica described the measure in similar terms: "This is an experiment. We can make a huge contribution to human kind."

Game-changer

First proposed by members of Mujica's left-leaning Frente Amplio ("Broad Front") party, the measure does not promote the use of cannabis, its proponents say - advertisements for marijuana are prohibited. Rather, it is designed to offer an alternative to a law enforcement approach that has cost the world huge amounts of money with few results. Over the past 40 years, the United States alone has spent an estimated $1tn dollars in the so-called "war on drugs", according to figures from the Drug Policy Alliance. Still, the use of marijuana and other drugs remains widespread.

Supporters say the rationale behind the law is to counteract the effects of drug trafficking and take revenue away from black-market traffickers.

"Regulation offers more advantages than a ban," Uruguayan legislator Sebastian Sabini told Al Jazeera. "When you regulate an activity, you can potentially eliminate the black markets, and the activity generates taxes that in return can be invested in education, information and public health programmes."

Though it's the smallest country in South America with just over three million people, Uruguay is making a big splash with the new law. Mujica hopes the legislation will become a game-changer in the "war on drugs" strategy.

The United Nations has already said Uruguay's legislation violates the 1961 Single Convention on Narcotic Drugs, to which Uruguay is a signatory. The measure has also drawn criticism from Paraguay and Brazil, whose leaders have expressed concerns that the drug might end up spilling across Uruguay's borders.

However, in a continent where the "war on drugs" has been blamed for thousands of murders and where drug trafficking is at crisis levels, the momentum for a different approach is building. "I think the debate is out there, and Uruguay is putting an option on the table that could be studied and adopted to other national realities in Latin America. I think this is going to have a huge impact in the antidrug trafficking policy in the whole region, offering a concrete answer," Hetzer said.

A lost war?

Support has come from Colombia, Guatemala, and Mexico, all countries that have received US aid to continue the "war on drugs". The Uruguayan initiative followed proposals discussed at the Summit of the Americas held in Colombia last year. Those proposals called for legalisation and regulation. US President Barack Obama, whose country is the largest consumer of illegal drugs, rejected the proposal.

"The war on drugs - that is also a war on drug users - has been lost," said Pablo Galain, a senior researcher at Germany's Max Planck Institute for International Criminal Law. "Learning from this failed game, Uruguay offers a different alternative."

Whether this alternative will be a huge failure, an immense success, or adopted elsewhere has yet to be seen. But by legalising marijuana, Uruguay has shifted the terms of debate. "I think this is a change of paradigm on the international level," said Galain.

It certainly has changed the game within Uruguay. Activists like Vaz are already looking to the next steps. "The time of fighting, protesting, asking for our rights and campaigning is over," he said. "Now it is about time to build things."