Regarding the op-ed "Medical marijuana laws make a farce of medicine" (March 7): While demanding for the FDA to make determinations regarding the safety and efficacy of marijuana may be appealing, it remains at this time politically unfeasible. That is because the cannabis plant, and all of its organic therapeutic properties, are classified under federal law as schedule I prohibited substances — the most restrictive classification possible.

The FDA exists to determine whether patented products from private companies can be brought to market. Since the present law forbids any legal private manufacturers to exist, there remains no entity available to conduct the sort of research and development necessary to trigger an FDA review.

That is not to imply that cannabis could not meet the objective standards or safety and efficacy. Given the substance's several-thousand-year history as a medicine, low toxicity and inability to cause lethal overdose in humans, cannabis is arguably safer than most conventional therapeutics.

Nonetheless, the longstanding politicization of cannabis precludes the FDA or any other scientific agency from being the final arbiter of cannabis policy. That responsibility lies solely in the hands of Congress and the Drug Enforcement Administration. It is they, not the FDA, that must ultimately bring logic and consistency to America's marijuana policies.

Paul Armentano, Washington

The writer is deputy director of NORML, the National Organization for the Reform of Marijuana Laws.