Could Mexican cities become Latin Amsterdams, flooded by drug users seeking penalty-free tokes and toots?

That is the fear, if somewhat overstated, of some Mexican officials, especially in northern border states that serve as a mecca for underage drinkers from the United States.

The anxiety stems from the Mexican legislature’s quiet vote to decriminalize the possession of small amounts of marijuana, cocaine, methamphetamine and other drugs, an effort that in the past proved controversial.

There’s been less protest this time, in part because there hasn’t been much publicity.

Some critics have suggested that easing the punishment for drug possession sends the wrong message while President Felipe Calderon is waging a bloody war against major narcotics traffickers. The battle between law enforcement authorities and drug suspects has claimed more than 11,000 lives since he took office in late 2006.

But it was Calderon who proposed the decriminalization legislation.

His reasoning: It makes sense to distinguish between small-time users and big-time dealers, while re-targeting major crime-fighting resources away from the consumers and toward the dealers and their drug lord bosses.

“The important thing is . . . that consumers are not treated as criminals,” said Rafael Ruiz Mena, secretary general of the National Institute of Penal Sciences. “It is a public health problem, not a penal problem.”

The legislation was approved at the height of a swine flu outbreak that dominated the public’s, and the world’s, attention. Meeting at times behind closed doors, the lower and upper houses of Congress passed the bill in the last days of April. It now awaits Calderon’s signature.

The bill says users caught with small amounts -- 5 grams of marijuana, 500 milligrams of cocaine -- clearly intended for “personal and immediate use” will not be criminally prosecuted. They will be told of available clinics, and encouraged to enter a rehabilitation program.

Up to 40 milligrams of methamphetamine, a synthetic and especially harmful drug, is permitted under the legislation, as is up to 50 milligrams of heroin.

In May 2006, then-President Vicente Fox, of the same right-wing party as Calderon, vetoed a similar bill that he initially had supported. He backed down only under pressure from the Bush administration, which complained that decriminalization for even small amounts could increase use.

But with about two weeks to go before crucial mid-term elections in which his party is struggling to maintain control of Congress, Calderon cannot afford to be seen as bowing to the United States, analysts say.

Already under intense criticism for the drug-related violence, Calderon needs to maintain good relations with his nation’s Congress, where much of the opposition voted in favor of the decriminalization bill.

And so, political observers say, he probably will sign it into law. Calderon’s office declined to comment for this article.

So far, the U.S. government has not publicly objected to the legislation. Michele Leonhart, acting director of the U.S. Drug Enforcement Administration, however, said in April that legalization “would be a failed law enforcement strategy for both the U.S. and Mexico.”

Mexican officials emphasize that they are not talking about legalization, but decriminalization. Courts now decide on a case-by-case basis whether and how to punish first-time drug-use offenders. There has been no standard criteria.

Calderon originally wanted the bill to allow users caught with amounts within the limits to avoid jail time only if they agreed to rehabilitation. But the bill was changed to say only that treatment would be encouraged.

Then Calderon sought a provision in which a third-time offender would be obliged to seek treatment. That measure was removed, Ruiz Mena said, after debate over whether mandatory rehabilitation is ever effective.

Mexico is woefully under-equipped to handle a rising drug-abuse problem.

For decades the country was a transit point for cocaine, marijuana and other drugs headed to the U.S. But recently, domestic consumption has risen. A 2007 study by the government found the number of addicts in Mexico to have doubled in the previous five years.

Drug abuse has grown worse in part because some of the cartels pay their people with cocaine or other drugs.

Clinics and other institutions that specialize in treatment and prevention have not kept up with the trend. The government is building 310 centers to improve care, but experts say that is not enough.

The decriminalization legislation has been criticized by religious leaders and several officials in the northern border states, who fear that “drug tourists” will begin flocking to towns and cities already besieged by violence.

“Allowing the carrying of certain amounts of drugs will create more consumers,” Oscar Villalobos Chavez, social development secretary for Chihuahua state, which borders Texas, told local reporters.

An editorial in the official magazine of the Roman Catholic Church criticized legislators for relaxing the law “when faced with the highly contagious and lethal sickness that drug addiction represents.”

Mary Ellen Hernandez, director of the Rio Grande Safe Communities Coalition in El Paso, across the border from blood-soaked Ciudad Juarez, said she worried that decriminalization would lure Americans into a drug world they aren’t prepared for and increase violence on both sides of the border.

“Already, the drugs that don’t come over into the U.S. are being handed out by dealers to younger and younger children [in Mexico], 8, 9, 10-year-olds, hooking them,” said Hernandez, whose agency specializes in drug prevention. “And then [the youths] steal to feed the habit.”

The legislation “is very disturbing and I think it will make things worse,” she said.

Except for the relatively few voices, however, there has been minimal protest over the law, and some praise.

Luciano Pascoe, vice president of the small left-wing Social Democratic Party, said the law was a positive “first step” that helped “shatter the stigma that consumers are criminals.”

His party is running in next month’s elections on a platform that includes legalization of all drugs as a way to make trafficking less lucrative.

It is not known whether that position has anything to do with four of his candidates being attacked in recent weeks. None was seriously injured.

wilkinson@latimes.com