At last we’ve turned the corner in the war on drugs. Attorney General Janet Reno and Treasury Secretary Robert E. Rubin announced more than 100 indictments and the seizure of some $150 million from Mexican banks, surely a successful conclusion to “the largest, most comprehensive drug money laundering case in history.” The druglords must really be on the ropes now.

But careful news watchers have heard those words before. It seems that not a week goes by without a report of “New Hampshire’s biggest drug bust,” “the biggest drug bust in middle Georgia history,” “the largest drug bust ever in the United States outside of Florida,” or — drum roll, please — “the largest drug bust in history.”

Law enforcement agents and journalists both love those stories — they publicize the “success” of the war on drugs, and they offer the journalists great visuals and great numbers. Helpful police flacks always provide some sexy dollar figures — cocaine with a street value of $3.3 million, $20 million, $73 million, $2 billion.

In a 1991 San Francisco case, billed as the biggest heroin bust ever, television cameras panned over 59 boxes containing 1,080 pounds of heroin — enough to supply each of the country’s estimated 500,000 heroin addicts for a month. Drug war officials said the street value of the heroin was $2.7 billion to $4 billion.

It’s true that the drug warriors are interdicting more drugs at our borders all the time. Seizures of cocaine rose from 20,000 pounds in 1983 to 179,000 pounds in 1989 to 239,000 pounds in 1997. But does that indicate success? More likely, it means that more drugs are crossing our borders and officials are interdicting about the same percentage as before.

As Mark A. R. Kleiman, a specialist on drug policy at Harvard University, said about the California raid, “For any shipment like this that you catch, you can assume that many more get through.”

When Americans read about ever-larger drug busts, or when we watch television shows about drug enforcement, we get the impression that drug enforcement agents are clever and innovative, always staying one step ahead of the sinister pushers. But in reality the drug distributors are the innovative ones — because they have a financial incentive to be.

The Drug Enforcement Administration and other law enforcement agencies are bureaucracies, and like all bureaucracies they tend to be inefficient. Police officers and drug agents get paid whether they slow drug traffic or not. In fact, they may receive more funding if the drug problem gets worse. Drug dealers, on the other hand, are entrepreneurs. If they outwit the officers, they make big money. That economic incentive spurs creativity, innovation, and efficiency.

Every week brings reports of innovations in drug smuggling: people who swallow heroin and carry it into the United States in their stomachs, drugs placed in the luggage of unaccompanied children on international flights, cocaine implanted in a passenger’s thighs — and those are just the methods police have discovered.

Recently, partly because the Supreme Court approved surveillance flights over private property to search for marijuana fields, marijuana growers have been moving indoors and underground. In November 1990 five subterranean marijuana farms were found by law enforcement officials in Southern California and Arizona; imagine how many were not found. One near Lancaster, California, cost about $1 million to build, police said, and had the potential to produce an annual profit of $75 million from 8,500 plants harvested four times a year.

Around the world, drug enforcers face what Ethan Nadelmann of the Lindesmith Center calls the “push-down/pop-up factor”: push down drug production in one country, and it will pop up in another. Marijuana and opium can be grown almost anywhere, and coca is being grown in places previously considered unsuitable.

As long as Americans want to use drugs, and are willing to defy the law and pay high prices to do so, drug busts are futile. Other profit-seeking smugglers and dealers will always be ready to step in and take the place of those arrested.

“We’ve cut off the head of the dragon,” said Robert Bender, head of the DEA’s San Francisco office, in announcing the 1991 heroin bust.

But in the years that followed, the DEA discovered that it had cut off the head, not of a dragon, but of a Hydra — the nine-headed monster in Greek mythology that couldn’t be killed because whenever one of its heads was cut off, two more grew to replace it. Now, we’ve cut off 100 heads of the drug-smuggling cartels. Will 200 more grow back to replace them?