Mexico’s capital is often thought of as a secular bubble inside a Catholic nation. In 2007, city authorities legalized abortion; in 2010, gay marriage was allowed; and next month the city’s lawmakers are poised to rethink its policy on marijuana possession.

But as the city inches toward decriminalizing pot, the impact of such a move has major implications that go beyond its nine million residents. Other states, including Morelos, Veracruz, and Oaxaca, could follow Mexico City's lead, presenting a challenge to President Enrique Peña Nieto who has argued against the legalization of marijuana as his country continues its war against drug traffickers.

The proposal – which will be submitted to the Mexico City legislative assembly in two weeks, according to the office of the bill's sponsor – would implicitly legalize up to 40 grams of marijuana, assigning it a legal classification called “zero priority.” The law would send a message to police not to take action if they witness cannabis dealings by any of the city’s estimated 85,000 users.

Carlos Zamudio Angles, an analyst with the Collective for an Integral Drug Policy, a Mexico City-based think tank that favors decriminalization, argues that police corruption makes this new law necessary. In a June 2013 report, the think tank said that two out of three marijuana users had reported bribing cops in order to avoid being detained.

Details on how a newly decriminalized market would be regulated have not been released, but the measure would be the first step in a broader legalization scheme, Mr. Zamudio says. Before proceeding further, however, lawmakers would likely wait and see how President Peña Nieto’s government reacts.

"The intent of the initiative is to gradually regulate the market," he says.

A spokesperson for Peña Nieto's office declined to comment about whether the president would challenge the law, if adopted, but said that "it is an issue exclusively related to the city’s government."

Vidal Romero, a professor of political science at the Mexico Autonomous Institute of Technology, says Peña Nieto would likely oppose the proposal, but would probably not block its implementation. That is, unless it became extremely unpopular on a national level.

National polls show that Mexicans generally oppose marijuana legalization, says Mr. Romero, who studies drug policy. But when the same question is asked alongside contextual information about drug violence, the responses swing in the other direction.

An August poll conducted by the strategic communication cabinet, a Mexican public opinion research firm, found that 49.6 percent of Mexicans are fully opposed to legalizing marijuana. The question asked "How much do you agree or disagree with the legalization of marijuana in our country?"

The state of Morelos, which lies directly south of Mexico City, has been hit hard by drug trafficking violence. Its governor, Graco Ramírez, has called for decriminalizing the sale of marijuana as a way to protect the residents of his state.

“Decriminalizing marijuana would be a very important change of strategy for lowering the level of violence that exists because it is associated with illegal trafficking," Mr. Ramírez said at a press conference last summer.

Fighting criminal violence by dismantling prohibition laws is a stark change to the military strategy that has been carried out by Mexico over the past 7 years – sometimes with the help of United States law enforcement.

Michael Braun, the former director of operations for the Drug Enforcement Administration who runs Spectre Group International, a security consultancy, argues that legalizing marijuana would have little effect on the cartels because much of their revenues come from other substances.

“Mexico City, if they think for a minute that legalizing user amounts of marijuana is going to somehow have an impact on the cartels, they're not," Mr. Braun says. "They all operate like a Fortune 100 corporation. Over the last 15 to 20 years, they've diversified their product lines."

Get the Monitor Stories you care about delivered to your inbox. By signing up, you agree to our Privacy Policy

Like Braun, the US Department of State, which oversees much of the US's aid to Mexico, is skeptical about whether marijuana legalization helps to improve the dangerous conditions presented by drug use and trafficking.

The US drug control strategy "rejects legalization as a silver bullet," the department said in an emailed statement to the Monitor.