Last week, Oregon joined Colorado and Washington in implementing a commercial cannabis market. Alaska, which also legalized marijuana through a ballot initiative, is expected to begin retail sales sometime next year.

Recreational marijuana remains illegal under federal law. In fact, the Controlled Substances Act puts cannabis in the same category as heroin and classifies the plant as having a greater potential for abuse than cocaine. But President Barack Obama, who once said marijuana was no more harmful than alcohol, has declared a shaky ceasefire in the war on weed.

In 2013, the Department of Justice issued a memorandum that provided "guidance regarding marijuana enforcement." It advised federal prosecutors not to interfere in those states where cannabis is now legal and effectively regulated. The president said the country would "see what happens in the experiments in Colorado and Washington" - and now Oregon as well.

"In those states, we recognize that the federal government doesn't have the resources to police whether somebody is smoking a joint on a corner," Obama said in an interview with CNN in 2014.

According to Ballotpedia, which tracks legislation, some 12 states could vote on initiatives to legalize marijuana in the coming year. The movement to end prohibition at the local level in the United States is rattling the foundations of US drug policy.

US as global drug cop

The principal legal foundation of the global war on drugs is a UN treaty. The 1961 Single Convention on Narcotic Drugs outlawed marijuana, cocaine, heroin and a host of other substances for anything other than medical or scientific purposes. The United States was the prime sponsor of this convention, which has now been adopted by nearly every country in the world.

"The US used its new superpower ascendancy in the postwar years and with the dawn of the UN to push through a much more restrictive set of agreements," John Walsh, an expert on international drug policy at the Washington Office on Latin America, told DW.

The goal was to suppress the production and limit the consumption of those outlawed drugs, including marijuana. At home, the United States waged its war on drugs with police, courts and prisons. US officials often viewed foreign police forces as inadequate, and so the United States provided military assistance, particularly to Latin American countries, and deployed its own forces to conduct surveillance.

"Realizing the United States was very intent on this strategy, Latin American elites have often had a hard time resisting," Walsh said. "Even when they realized a strategy of drafting the military into a law enforcement effort is not going to end well, especially in countries where the military has been known to leave the barracks and take political power."

One-size-fits-all approach questioned

By allowing the sale of recreational marijuana to move forward at the state level in the United States, the Obama administration has placed the 1961 Single Convention on Narcotic Drugs into question.

"It sends the message that the US is a much less determined policeman and the US is willing to tolerate deviations from policies that were previously unthinkable," Vanda Felbab-Brown, an expert on global drug policy at the Brookings Institution, told DW.

In 2013, the South American nation of Uruguay became the first country in the world to legalize marijuana on a national level. According to Walsh, the shift in the US on marijuana is opening up space for other countries, mostly in Latin America, to experiment with drug reform.

"The question is can countries innovate and find better ways to their ultimate goal, which is promoting public health and public safety, through strategies that differ from prohibition," Walsh said. "We are seeing the first test of that in the case of cannabis, and I think we'll see more."

Felbab-Brown said the US's deviation from the terms of the narcotics treaty would be a major subject of discussion when the UN General Assembly holds a special session on drugs next April. But, even as the United States has softened its position on marijuana, other countries remain as steadfast as ever in waging the drug war.

"There are new policemen like Russia and China who have no willingness to allow deviation from existing very primitive approaches," Felbab-Brown said.

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