When the Uruguayan president José Mujica was asked about his proposal to make a historic break with global prohibition and put in place a legal, state-controlled market for cannabis, he replied: "Someone has to be first."

In fact, recent years have seen reforms to cannabis policy and law proceeding apace around the world. The trend for decriminalisation of possession for personal use (with civil or administrative penalties replacing criminal ones) has spread across much of Europe, Latin America, and beyond. Some countries have gone further, finding various ways around the strictures of international prohibition (under the three UN drug conventions) to have de-facto legal supply as well. The famous Netherlands cannabis "coffee shops" operate under a legal fudge in which their activities are technically illegal, but in practice are tolerated and licensed. The Spanish decriminalisation policy tolerates the personal possession of two plants and has allowed the creation of more than 300 cannabis co-operatives. These pool the allowances of all their members, then farm and supply the resulting grass on a non-profit basis to these members from premises managed by the co-operative.

Most surprising have been reforms in the US, the spiritual home of the "war on drugs" ethos and still its primary cheerleader internationally, despite more than 50% of Americans now supporting cannabis legalisation. Fourteen US states have decriminalised cannabis possession, and 17 now allow medical cannabis – in some cases with the distinction between medical and non-medical use becoming increasingly blurred. Most significant are the three state ballot initiatives, in Washington, Oregon and Colorado being voted on in November, which will legalise and regulate cannabis markets for non-medical use.

While the US initiatives are groundbreaking and, if current polling holds up, may well be the first real cracks in the edifice of global prohibition, they are, like most reforms, being led by (excuse the pun) grassroots campaigns. One of the unique aspects of the Uruguayan legalisation proposal is that it is government led. Indeed, the Mujica proposal for a state monopoly on cannabis production and supply has, ironically, run into conflict with another Uruguayan bill promoted by cannabis activists that seeks to decriminalise personal consumption of up to eight plants and establish co-operatives along the lines of the Spanish model.

While unlikely to prove popular in the US, the idea of government monopoly is appealing in many ways, certainly for a pioneering initiative such as this. It is vitally important to learn from the mistakes made with alcohol and tobacco regulation. That means avoiding over-commercialisation and, while allowing legal availability to adult consumers, putting in place a regulatory framework to minimise health and social harms, rather than maximise profits. What this means in practice has been explored in some detail in Transform's Blueprint for Regulation which outlines potential controls over products (potency, price, information on packaging etc), vendors (licensing, vetting, training requirements), venues for sale and consumption (location, appearance, opening hours), and availability (age access controls, membership clubs). A responsible government is a far better entity to develop such a model than the free market.

The regional context of the Mujica proposal is also critical. The debate on drug law reform in Latin America has accelerated, with multiple heads of state now openly tabling the possibility of wider reforms including legalisation, and the Organization of American States currently reviewing all the options, as frustrations have grown with the deteriorating security situation and violence related to the drug trade. The perception is that Latin America carries an unacceptably heavy burden for drug consumption in the US and Europe, and that the externally imposed solution, a military and police-led war on drugs, is costly and counterproductive – as Mexico in particular has found out to its cost in recent years.

The Mujica proposal is, perhaps unsurprisingly, couched within a bill of security measures and is being primarily promoted on that basis and, as is often the case with drug reform legislation, it includes provisions for increased penalties for traffickers. It also faces a number of other hurdles; it needs to be reconciled with the decriminalisation bill, and it does not enjoy majority public support (40% are in favour). Then are the objections from the guardians of the prohibitionist status quo, the US and the UN drug agencies.

If or when the Uruguayan initiative will be realised remains impossible to say – they may be first, they may not. But it is now clear that someone will be, and soon. After decades of counterproductive failure, the era of blanket global prohibitions on drugs is finally coming to an end.