Much is made of how President Obama's position on same-sex marriage has "evolved" to an endorsement of legalization. One hopes his position on the atrocity called the "war on drugs" is evolving.

It's not really a war on drugs. It's a war on people, most of whom have committed no violence or other aggression against person or property. Those who do commit violence are encouraged to do so by the very "war on drugs" that Obama and other enlightened leaders so enthusiastically support. Black markets often feature violence — precisely because they are illegal. Decriminalize the activity, and the violence goes away.

America had a natural experiment in this principle: Prohibition. When the manufacture and sale of alcohol were made illegal by constitutional amendment in 1920, booze didn't disappear from society. It simply went underground to be dominated by those with a comparative advantage in thuggery. Ending prohibition brought alcohol into the legitimate market (although unfortunately regulated and licensed). The violence related to the manufacture and sale of alcohol went away.

Thus the violence perpetrated by Latin American drug cartels and gangs in the United States is not an argument against decriminalization. It's an argument for it.

It's well known that an unconscionably high percentage of the American population is in prison. We can thank the government's persecution of drug commerce for that shameful fact. It is also increasingly understood that militarized police drug raids terrorize people every day, often killing individuals who were not even intended as targets. The American people should demand that this systematic oppression be stopped. The police have become the enemy of Americans, mostly but not exclusively members of minority communities.

The raids that end in death at least make the headlines and perhaps upset people for a short while. But another part of the war on drug commerce gets less attention. When consenting people buy and sell drugs, there is no victim to complain. So to make arrests, police need to trap people — many of them young — in drug transactions and then threaten them with long jail terms unless they become informants. Many take these deals — against their deepest beliefs — for fear of having their lives destroyed by felony convictions and time in the hell holes we call prisons. They proceed to set up drug deals with friends and family members just so they can produce cases for the cops and leniency for themselves.

Can there be a worse indictment of the sadistic government crusade against drugs? What possible good is done by police blackmailing the most vulnerable, even helpless, people into informing on others? Cooperation with the police under these circumstances, despite the duress, is morally wrong — but we mustfirst condemn the police — and politicians who back them — for putting people in this situation. What kind of society is this? It does not deserve to be called humane.

But drugs are dangerous, people say. It's about time this empty slogan was thrown on the trash heap. Illegal drugs are not illegal because they are dangerous. Other substances that can be used in harmful ways — most obviously alcohol — are legal. Many legal activities that people love to engage in are highly dangerous. Certain drugs have been singled out for prohibition historically not because they are especially dangerous but because they were associated with minority communities. The story of the "drug war" is not of a humane effort to create a healthy, safe society. It's a story of persecution and control — and of tax-funded largess for law enforcement and the "drug-rehabilitation" industry.

Politicians in Latin America are beginning to understand that the drug wars tearing their countries apart would end overnight if the drug industry were decriminalized. No one would be more opposed to decriminalization than the drug lords, because they'd lose their de facto monoplies.

But who patronizingly insists that Latin America stay with its destructive policy? President Obama and his secretary of state, Hillary Clinton. They would rather see the violence continue and spill over into the United States than admit they are wrong.

No drug could do even a tiny fraction of the damage that the drug war does. Mr. Obama, when will your position evolve?

Sheldon Richman is senior fellow at The Future of Freedom Foundation in Fairfax, Va., author of Tethered Citizens: Time to Repeal the Welfare State, and editor of The Freeman magazine.