Time and again, the Obama administration has voiced its allegiance to science on politically controversial issues of environment, energy and health.

We think the administration ought to be true to this laudable principle on the question of medical marijuana.

The controversies that have erupted in many states over the legalization and regulation of medical marijuana could be alleviated if the federal government sponsored more and better research into the efficacy of marijuana in treating a variety of medical conditions.

That way, science could trump the half-baked justifications from some advocates who make all manner of claims about the medicinal powers of marijuana.

If marijuana were an FDA-approved drug with recognized benefits for certain, specific medical conditions, it could be prescribed like any other drug.

The U.S. Drug Enforcement Agency contends prescription Marinol — which contains THC, the main active ingredient in marijuana — is an appropriate substitute for medical marijuana.

The DEA says there are no drugs approved by the Food and Drug Administration that are smoked. The chemicals and carcinogens that are byproducts of smoking create a whole new set of health concerns.

Furthermore, the DEA argues that even though morphine is a drug with significant medical value, the FDA does not suggest smoking opium or heroin.

However, medical marijuana advocates argue that Marinol doesn’t provide relief to all patients. Some patients find alleviation of symptoms only from the fuller range of compounds contained in natural marijuana.

The anecdotal stories from people with serious illnesses are not to be dismissed. However, it remains an argument without a definitive answer.

Clearly, more research needs to be done.

A New York Times story earlier this month said only a few small- scale studies have been done, and they are decades old, suggesting that smoked marijuana can provide relief when Marinol is ineffective.

The Wall Street Journal also ran a story on this topic this month, saying an American Medical Association review found there have been fewer than 20 randomized, clinical trials of smoked marijuana.

In all, the studies involved about 300 people, which is far short of the typical number required before a drug is approved for widespread use in the United States.

Much of the difficulty in regulating marijuana derives from the inability to truly classify it as a medicine. Medical marijuana occupies a netherworld between homeopathic remedies and federally approved drugs.

Its complicated status is made even more volatile by the fact that it’s illegal under federal law, yet ensconced in the Colorado state constitution.

If medical marijuana were a prescription drug, it would fit neatly into existing regulatory and law enforcement structures.

Now all that’s necessary is the science to define its legitimate uses.