President Donald Trump has finally outlined a comprehensive approach for dealing with the nation’s opioid crisis. He appears to understand that the issue is complex. But his plan to address it is precisely backward in its priorities, underfunded and vague about how it would be carried out.

In a long and rambling speech last week in Manchester, N.H., the president seemed most enthusiastic about imposing the death penalty on major drug dealers, increasing mandatory minimum sentences for lesser drug dealers, building his famous wall along the border with Mexico to keep drugs from coming into the country, and producing a series of ominous television commercials.

Never mind that most hard drugs enter the United States through legal border crossings.

The Manchester speech was Trump’s third crack at the opioid issue. Opioid addiction disproportionately impacts low-income rural voters who are a major part of his base.

Since 1980, when Congress began enacting tougher penalties for drug dealing, the number of people incarcerated for the crime has increased from 15,000 to 450,000. Drugs are still easily available. Nor is it clear that executing drug dealers would even be constitutional.

Trump believes deeply in the power of TV, so he wants to “spend a lot of money” producing some “very, very bad” (meaning scary) commercials that will convince kids to avoid drugs.

If the failed four-decade war on drugs has taught us anything, it’s that when “just say no” is the primary appeal to potential users, you should rethink the plan.