MEXICO CITY — In two weeks, Californians will decide whether to legalize small amounts of marijuana for recreational use, in a vote that polls show could be close.

Now, for a change in the drug war, it is Mexico wondering about the possible spillover, this time of an idea. Will such a bold step by its neighbor to the north add momentum to a burgeoning movement here for broad drug legalization?

The backdrop is the drug war, which has left Americans worrying about many of the ills that spill over the border: kidnappings, murders and, of course, drugs themselves. At the same time, Mexicans chafe at the guns flowing in from the States, the nearly 30,000 people killed in drug-related violence here in the past four years and the American demand and consumption that largely sustain the drug trade.

Small steps toward legalization have already been taken on both sides of the border. California, where medical marijuana has been legal under state law since 1996, this month made the punishment for possessing small amounts of the drug the equivalent of a speeding ticket instead of a misdemeanor. Last year, Mexico removed the penalty for possessing small quantities of a range of drugs, including cocaine, heroin and marijuana, though selling or producing them remain prohibited.

But the similarities pretty much end there. Even those here who are pushing for the legalization of drugs — and in some circles “hard drugs,” like cocaine and heroin — concede that any major change in Mexico would probably be years away, regardless of what happens in California.

For one thing, President Felipe Calderon, who has expressed frustration with the prospect of a “yes” vote in California as another sign of Americans’ failure to bring their drug consumption under control, has not budged from his staunch opposition to legalization.

Because a rising number of intellectuals and some members of the political elite — including his immediate predecessor, Vicente Fox, and ministers who served under him — are advocating legalization, Calderon has called for a debate on the subject.

That raised eyebrows, feeding speculation that a change could be under way. But since then, Calderon has not done much to encourage it. In fact, two weeks after Calderon called for a debate, his health minister called legalization “absurd.”

Few people in the corridors of power have promoted the idea, and most polls show little support for legalization, particularly outside the more liberal confines of Mexico City. But even if the populace were clamoring for a change, Mexico, unlike California, is not known for citizen-driven lawmaking.

“Reform issues in Mexico tend to be top-down,” said Daniel Lund, a pollster with the Mund Group here. “If nobody in authority is championing an issue, it doesn’t have oomph.”

Advocates for legalization in Mexico and California insist the motivation is not primarily to make it easier to get high.

In California, supporters of Proposition 19, which would allow anyone over 21 to possess up to an ounce of marijuana and permit municipalities to tax and regulate it, have pushed the notion that it could raise $1.4 billion in taxes while diverting law enforcement and prison resources to more serious crimes.

In Mexico, the main selling point has been that drug-trafficking organizations would be crippled by the creation of a legal, regulated market for their product that would cut off their illicit financial pipeline.

But as the vote in California draws closer, skepticism is emerging.

A study released last week by the nonpartisan RAND Drug Policy Research Center in Santa Monica, Calif., cast doubt on whether legalization in California would financially harm Mexico’s drug traffickers.

It argued that cutting out the California market would reduce their revenue only 2 percent to 4 percent, in part because much of the marijuana consumed in California is already grown there, and the drug organizations derive their income from many sources. The study did, however, suggest that if low-cost, high-quality California marijuana was smuggled across the United States, the cartels could lose 20 percent of their income from exports.

Federal officials in the United States hardly see the proposal as a boon.

Attorney General Eric H. Holder Jr. said Friday that the Justice Department would use federal law to prosecute “those individuals and organizations that possess, manufacture or distribute marijuana for recreational use,” throwing into doubt whether legalization would actually go forward.

Still, hardly a day passes here without some new wrinkle in the discussion.

Nexos, a magazine that has been sympathetic to Calderon’s approach, devoted its issue this month — with a large marijuana leaf beckoning from newsstands — to advocating legalization. The back-and-forth in California regularly makes headlines.

Jorge Castaneda, the foreign minister under Fox, is among the chief promoters of legalization and says he believes the debate is shifting in his favor. He notes that four of six presumed presidential candidates for 2012 told Nexos that legalization should be at least considered if California approved it.

Just as legalizing alcohol helped dismantle organized crime in the United States in the 1930s, he says, legalizing marijuana could devastate major drug trafficking organizations. While Calderon and other political leaders do not seem to embrace legalization, “what does he do on the morning of Nov. 3?” Castaneda asked.

“It is going to be impossible to ask Mexican society to put up with the number of lives at risk and the violence for a fight that Americans, or at least Californians, would have said they don’t want to fight anymore,” he said.

But some analysts think the debate here has given short shrift to another fundamental question: Does Mexico, which has enough trouble collecting existing tax revenue and regulating legal medications, have the institutional capacity to take on regulation of marijuana, let alone cocaine or heroin?

And there is the likelihood that any curb on the drug markets would drive the cartels to expand their increasingly diverse rackets in smuggling, extortion and kidnapping.

With a chronic lack of strong anti-addiction and anti-consumption programs, Mexico would probably experience more people taking drugs and provide little help for them, said Edgardo Buscaglia, a professor at the Autonomous Technological Institute here who has studied organized crime for years.

“To think organized crime would cease to exist is nonsense,” he said. “They are like any rational business, and they will go into other businesses for the rate on return.”

Marijuana and other drugs are readily available in several neighborhoods here, “like candy,” in the words of Victor Arroyo, 24, who said he was addicted to marijuana. Without using it several times a day, he said, he gets headaches and does not feel right.

The only change legalization would bring, he predicted, would be that consumption would be more out in the open, something he laments, since he has seen children as young as 9 smoking marijuana in the public housing project where he lives.

“It would really be the same,” he said, “or maybe worse.”

© 2010 The New York Times Company