THE nota roja, a section reporting the previous day's murders and car crashes in all their bloodstained detail, is an established feature of Mexican newspapers. It is also an expanding one, as fighting over the drug trail to the United States inspires ever-greater feats of violence. Last month in the northern state of Durango, a group of prisoners was apparently released from jail for the night to murder 18 partygoers in a next-door state. A few days later, 14 inmates were murdered in a prison in Tamaulipas. In all, since Felipe Calderón sent the army against the drug gangs when he took office as president almost four years ago, some 28,000 people have been killed, the government says. There is no sign of a let-up, on either side.

So it came as a surprise when on August 3rd Mr Calderón called for a debate on whether to legalise drugs. Though several former Latin American leaders have spoken out in favour of legalisation, and many politicians privately support it, Mr Calderón became the first incumbent president to call for open discussion of the merits of legalising a trade he has opposed with such determination. At a round-table on security, he said this was “a fundamental debate in which I think, first of all, you must allow a democratic plurality [of opinions]…You have to analyse carefully the pros and cons and the key arguments on both sides.” It was hardly a call to start snorting—and Mr Calderón subsequently made clear that he was opposed to the “absurd” idea of allowing millions more people to become addicted. But it has brought into the open an argument that appears to be gaining currency in Mexico.

The president spoke despite some recent success for his military campaign, with several important mafia bosses captured or killed. The latest was Ignacio Coronel, whose killing last month when the army raided his house was important for the government, which has been accused of giving the Sinaloa mob an easier ride than other gangs. (A car-bomb last month in Ciudad Juárez, on the border with the United States, may have been planted by rival traffickers to draw in America as a “neutral referee”, speculates Stratfor, a Texas-based security-analysis firm.) Half a dozen government agencies are said to be searching for Joaquín “El Chapo” Guzmán, Sinaloa's boss and the country's most notorious trafficker. Officials claim success in strengthening the police and bringing recalcitrant state governors into line.

Yet kicking the hornets' nest has provoked stinging turf battles, increasing the body count. In Cuernavaca, a pretty town near Mexico City that is popular with foreigners learning Spanish, a drug lord was killed by the army in December. Since then a spate of hangings around the edge of town has indicated that a gruesome succession battle is under way.

Many Mexicans are starting to weary of the horror. Four days after Mr Calderón's cautious call for debate, Vicente Fox, his predecessor as president, issued a forthright demand for the legalisation of the production, sale and distribution of all drugs. Legalisation “does not mean that drugs are good…rather we have to see it as a strategy to strike and break the economic structure that allows mafias to generate huge profits in their business, which in turn serve to corrupt and to increase their power,” he wrote on his blog. Ernesto Zedillo, Mexico's president from 1994 to 2000, last year jointly authored a report with two other former heads of state, Brazil's Fernando Henrique Cardoso and César Gaviria of Colombia, calling for legalisation of marijuana (ie, cannabis). Mr Cardoso later said the same of cocaine.

It is easier to be radical in retirement than in office. As president, Mr Fox backed down after George W. Bush's administration protested against his attempts to decriminalise possession of drugs. (Last year Mexico decriminalised possession of small quantities, a change designed mainly to limit the scope for police to demand bribes.) But it is striking that all these former leaders are middle-of-the-road moderates, not wild-eyed leftists.

Some in the United States are now pushing in the same direction. Californians will vote in November on whether to legalise and tax the sale of marijuana to adults (it is already legal to buy and sell pot for medical complaints, which some liberal doctors consider to include insomnia, migraines and the like). The initiative may fail: polls show opinion evenly divided, and it would also have to survive scrutiny by federal authorities. Although Barack Obama's administration has stopped prosecuting the sale of “medical” marijuana, it is opposed to legalisation.

But were the proposal to pass it would render Mexico's assault on drug traffickers untenable, reckons Jorge Castañeda, a former foreign minister. “How would you continue with a war on drugs in Tijuana, when across the border grocery stores were selling marijuana?” he asks.

The problem is recognised by the politicians too. Nexos, a Mexican magazine, recently asked six likely contenders for the presidency in 2012 whether Mexico should legalise marijuana if California did. One said no, but four answered yes, albeit with qualifications. Enrique Peña Nieto, the early leader in the polls, said carefully: “We would have to reconsider the view of the Mexican state on the subject.”

Since marijuana provides the gangs with up to half their income, taking that business out of their hands would change the balance of financial power in the drug war. But curiously, polls suggest that one of the groups most strongly opposed to the initiative in California is Latinos.