Amelioration of today’s drug problem requires Americans to understand the significance of the 80-20 ratio. Twenty percent of American drinkers consume 80 percent of the alcohol sold here. The same 80-20 split obtains among users of illicit drugs.

About 3 million people — less than 1 percent of America’s population — consume 80 percent of illegal hard drugs. Drug-trafficking organizations can be most efficiently injured by changing the behavior of the 20 percent of heavy users, and we are learning how to do so. Reducing consumption by the 80 percent of casual users will not substantially reduce the northward flow of drugs or the southward flow of money.

Consider current policy concerning the only addictive intoxicant currently available as a consumer good — alcohol. America’s alcohol industry, which is as dependent on the 20 percent of heavy drinkers as they are on alcohol, markets its products aggressively and effectively. Because marketing can drive consumption, America’s distillers, brewers and vintners spend $6 billion on advertising and promoting their products. Americans’ experience with marketing’s power inclines them to favor prohibition and enforcement over legalization and marketing of drugs.

But this choice has consequences: More Americans are imprisoned for drug offenses or drug-related probation and parole violations than for property crimes. And although America spends five times more jailing drug dealers than it did 30 years ago, the prices of cocaine and heroin are 80 to 90 percent lower than 30 years ago.

In “Drugs and Drug Policy: What Everyone Needs to Know,” policy analysts Mark Kleiman, Jonathan Caulkins and Angela Hawken argue that imprisoning low-ranking street-corner dealers is pointless: A $200 transaction can cost society $100,000 for a three-year sentence. And imprisoning large numbers of dealers produces an army of people who, emerging from prison with blighted employment prospects, can only deal drugs. Which is why, although a few years ago Washington, D.C., dealers earned an average of $30 an hour, today they earn less than the federal minimum wage ($7.25).

Dealers, a.k.a. “pushers,” have almost nothing to do with initiating drug use by future addicts; almost every user starts when given drugs by a friend, sibling or acquaintance. There is a staggering disparity between the trivial sums earned by dealers who connect the cartels to the cartels’ customers and the huge sums trying to slow the flow of drugs to those street-level dealers. Kleiman, Caulkins and Hawken say that, in developed nations, cocaine sells for about $3,000 per ounce — almost twice the price of gold. And the supply of cocaine, unlike that of gold, can be cheaply and quickly expanded. But in the countries where cocaine and heroin are produced, they sell for about 1 percent of their retail price in the United States. If cocaine were legalized, a $2,000 kilogram could be FedExed from Colombia for less than $50 and sold profitably here for a small markup from its price in Colombia, and a $5 rock of crack might cost 25 cents. Criminalization drives the cost of the smuggled kilogram in the United States up to $20,000. But then it retails for more than $100,000.

People used to believe enforcement could raise prices but doubted that higher prices would decrease consumption. Now they know consumption declines as prices rise but wonder whether enforcement can substantially affect prices.

Kleiman, Caulkins and Hawken urge rethinking the drug-control triad of enforcement, prevention and treatment because we have been much too optimistic about all three.

And cartels have oceans of money for corrupting enforcement because drugs are so cheap to produce and easy to renew. So it is not unreasonable to consider modifying a policy that gives hundreds of billions of dollars a year to violent organized crime.

Marijuana probably provides less than 25 percent of the cartels’ revenue. Legalizing it would take perhaps $10 billion from some bad and violent people, but the cartels would still make much more money from cocaine, heroin and methamphetamines than they would lose from marijuana legalization.

Sixteen states and the District have legalized “medical marijuana,” a messy, mendacious semi-legalization that breeds cynicism regarding law. In 1990, 24 percent of Americans supported full legalization. Today, 50 percent do. In 2010, in California, where one-eighth of Americans live, 46 percent of voters supported legalization, and some opponents were marijuana growers who like the profits they make from prohibition of their product.

Would the public health problems resulting from legalization be a price worth paying for injuring the cartels and reducing the costs of enforcement? We probably are going to find out.

georgewill@washpost.com