The current opioid crisis underlines the importance of curbing demand. This approach, with sufficient resources and the right message, could have a major impact similar to the campaign to reduce tobacco use.

We should also decriminalize the small-scale possession of drugs for personal use, to end the flow of nonviolent drug addicts into the criminal justice system. Several states have taken a step in this direction by decriminalizing possession of certain amounts of marijuana. Mexico’s Supreme Court has also declared that individuals should have the right to grow and distribute marijuana for their personal use. At the same time, we should continue to make it illegal to possess large quantities of drugs so that pushers can be prosecuted and some control over supply maintained.

Finally, we must create well-staffed and first-class treatment centers where people are willing to go without fear of being prosecuted and with the confidence that they will receive effective care. The experience of Portugal suggests that younger people who use drugs but are not yet addicted can very often be turned around. Even though it is difficult to get older addicted people off drugs, treatment programs can still offer them helpful services.

With such a complicated problem, we should be willing to experiment with solutions. Which advertising messages are most effective? How can treatment be made effective for different kinds of drugs and different degrees of addiction? We should have the patience to evaluate what works and what doesn’t. But we must get started now.

As these efforts progress, profits from the drug trade will diminish greatly even as the dangers of engaging in it will remain high. The result will be a gradual lessening of violence in Mexico and Central American countries.

We have a crisis on our hands — and for the past half-century, we have been failing to solve it. But there are alternatives. Both the United States and Mexico need to look beyond the idea that drug abuse is simply a law-enforcement problem, solvable through arrests, prosecution and restrictions on supply. We must together attack it with public health policies and education.

We still have time to persuade our young people not to ruin their lives.