The De Lorean drug case should, but won't, give a little new life to an old argument.

Accepted in England, but rejected here for the past half century, the argument proceeds from the well-demonstrated premise that hard-drug addicts will pay what is necessary to remain supplied with their drug of choice. Their addiction is both physical and psychological, and will induce the most scrupulous among them to knock over any law, bank, store or individual to obtain the means to secure the relief they seek.

In Britain, the morphine-plagued wounded of World War I and their hapless successors have secured such relief through government-sponsored and -monitored progams of clinical treatment with the drug of choice. Britain's addict population now numbers some 20,000. Our law was simpler: no hard drugs for anyone. King Canute also ordered the sea to recede. Our addict population has reached an approximate half-million. Now back to John De Lorean.

It has been reported that the 220 pounds or $24 million worth of cocaine police allege he received was the street value of one week's consumption in California. Inasmuch as addicts don't take holidays, 52 weeks at that rate would amount to nearly $1.25 billion per annum. How do addicts, other than the carriage trade, generate $1.25 billion a year? By stealing such cash as may be available, but more often property, which can be fenced for cash. A fenced item generally fetches at most a fourth of its value. Assuming $1 billion must be raised in this fashion each year, $4 billion worth of property must be stolen and fenced to keep the California crowd satisfied. That's real money, and would stimulate the underworld.

They see to it that the drug conduits from the jungles of two or three hemispheres to the streets of our major cities are open for business regardless of occasional embarrassments. Frequently, otherwise law-abiding folks are persuaded by the promised financial rewards to supplement the professionals in forming the chain from supply to demand. Successive generations of prosecutors, governors, attorneys general, congressmen, senators and presidential hopefuls can and, in fact, do stride to their several podiums and vow to "get tough" and thus put an end to this perniciious traffic. These worthies come and go, but the trade, like the river, goes on forever.

Private entrepreneurs should always receive the full force of punitive laws. But their decline will not occur until they are, in effect, dealt out of the equation. In this way, the addict's dependency would be both satisfied and treated at a modest cost compared with today's crime-inflated figures, the public would be spared a good measure of insecurity, violence and theft, and jails would be roomier.

But three other dependencies, each with real power, would be frustrated. They are organized crime and those elements of the enforcement and political communities that feed exclusively off the "crack-down" theory. One can confidently predict that this triple alliance will continue to find the will and the means to prevent a sane solution to the drug problem. The celebrated De Lorean case will itself eventually occupy a comfortably obscure niche in that continuing saga of self- deception we are pleased to call our drug policy.