IN NOVEMBER 57% of Californians voted to legalise the growing and use of marijuana for recreational purposes. Americans in seven other states and Washington, DC, are now, or soon expect to be, free to puff away at leisure, but liberalisation in the most populous border state will be felt acutely down south. Mexico has just marked the tenth anniversary of a war on drugs. It has spent millions of dollars on eradicating cannabis. Now it will abut a huge regulated market for the stuff—and one where 30% of the population is Mexican or Mexican-American. Changes in the United States may be prompting a rethink in Mexico, too—among ordinary people, policymakers and purveyors of pot alike.

Start with the citizens. Nearly a third of voters in Mexico currently support legalising marijuana for recreational use. Attitudes are mellowing: in 2008 only 7% approved of legal pot (see chart). Many Mexicans associate the herb with the horrors of the drug war, estimated to have cost more than 80,000 lives. For some this is a reason to crack down harder on it; for others, to take it out of the hands of criminals.