THE EFFORT to bring a marijuana initiative to the voters in November died last week because its volunteers didn't get enough people to sign petitions. The D.C. Marijuana Initiative sought to "remove criminal penalties and arrest procedures for the private possession or cultivation of marijuana by adults." George Farnham, the lawyer who headed DCMI, says a renewed effort will be made next year.

But getting enough signatures was not the only problem of DCMI. Its bigger problem was that the law it was supporting could not stand up to close examination. The law's principal fault was that it didn't distinguish between private possession of marijuana and possession iwth intent to sell. No difference was recognized between a man with a truckload of marijuana and a man with one joint. That failing extended to provisions permitting the growing of marijuana in the city. How large would a crop of marijuana have had to be before it was considered more than adoquate for the grower's personal use? And while the initiative would have prohibited the use of marijuana in public, it did not specify whether someone smoking in his own back yard or on his own front steps (private property in public view) would be in violation of law. Many others features of the proposed law were so vague as to invite abuse. It would have created more problems for government enforcement of marijuana laws than it would have resolved.

And while the proposal would have prohibited minors from using marijuana, it made no calculation of the effect that approved use of the drug by adults would have on teen-agers. Already too many teenagers drink alcohol and smoke marijuana, and the number appears to be increasing, according to government studies. Now DCMI would have us tell young people that the only reason not to try marijuana is that they are not 18 years old.

The truth is marijuana can be dangerous to young people. Studies have shown that it affects sexual development, it can jeopardize or retard emotional and intellectual growth in adolescents, and it can do more damage to lungs than tobacco does. To ignore all this would be to judge the drug by a far looser standard than sensible people wish to bring to bear on other substances -- whether food or drugs, household products or pesticides -- that can endanger health and life.

Certain personal uses of marijuana can be decriminalized to make law enforcement more effective and evenhanded, while not making that use an approved activity. But the broad-brush approach of the initiative in seeking to make marijuana use legal is not a satisfactory solution.