( Bernd Debusmann is a Reuters columnist. The opinions expressed are his own)

Tough marijuana laws are driving millions of Americans to a more dangerous mood-altering substance, alcohol. The unintended consequence: violence and thousands of unnecessary deaths. It’s time, therefore, for a serious public debate of the case for marijuana versus alcohol.

That’s the message groups advocating the legalization of marijuana are beginning to press, against a background of shifting attitudes which have already prompted 13 states to relax draconian laws dating back to the 1930s, when the government ended alcohol prohibition and began a determined but futile effort to stamp out marijuana.

How dismally that effort has failed is not in doubt. Marijuana is so easily available that around 100 million Americans have tried it at least once and some 15 million use it regularly, according to government estimates. The U.S. marijuana industry, in terms of annual retail sales, has been estimated to be almost as big as the alcohol industry — $113 billion and $130 billion respectively. On a global scale, marijuana is the world’s most widely used illicit drug.

Since the United States, and much of the rest of the world, plunged into a recession last year, the most frequently used argument in favour of legalizing marijuana has been economic: if it were taxed, the revenue would help stimulate economic recovery just as a gusher of dollars in fresh tax revenue from alcohol helped the United States pull out of the Great Depression after the 1933 repeal of prohibition.

That idea enrages some leading drug warriors, including the head of the United Nations Office on Drugs and Crime, Antonio Maria Costa. In the preface to the U.N.’s 2009 World Drug Report, he asks whether proponents of legalization and taxation also favour legalizing and taxing human trafficking and modern-day slavery “to rescue failed banks.”

Never mind that drug abusers hurt themselves and human traffickers hurt others. It’s the kind of topsy-turvy logic which has made sober discussion of national and international drug policies (largely driven by the United States) so difficult for so long.

The case for adding a compare-and-contrast dimension to the debate is laid out in a statistics-laden book to be published next month entitled “Marijuana is Safer, So why are we driving people to drink?” The authors are prominent legalization advocates – Steve Fox of the Marijuana Policy Project, Paul Armentano of the National Organization for the Reform of Marijuana Laws (NORML) and Mason Tvert, co-founder of SAFER (Safer Alternative for Enjoyable Recreation).

“The plain and simple truth is that alcohol fuels violent behaviour and marijuana does not,” Norm Stamper, a former Seattle police chief, writes in the foreword of the book. “Alcohol … contributes to literally millions of acts of violence in the United States each year. It is a major contributing factor to crimes like domestic violence, sexual assault and homicide. Marijuana use … is absent in that regard from both crime reports and the scientific literature. There is simply no causal link to be found.”

LACK OF COMMON SENSE

Violence committed by belligerent drunks apart, there is the question of which drug — marijuana or alcohol — is more harmful to your health. The authors cite government statistics and a long string of academic studies that show marijuana is less harmful.

According to the National Institute on Alcohol Abuse and Alcoholism, around 35,000 Americans die of alcohol-related diseases every year. That’s almost 100 a day. Add to this another 16,000 people killed in road accidents involving drunk drivers. There are no equivalent statistics for deaths linked to marijuana use.

Yet alcohol is legal, marijuana is not. The monumental lack of common sense in the attitudes of successive U.S. administrations towards marijuana is one of the explanations for a steady shift in public attitudes as reflected by opinion polls. In May, a Zogby poll found 52 percent support for treating marijuana as a legal, taxed and regulated substance.

Opposition to legalization, polls show, has been weakening over the past few years. Before 2005, no national poll showed support for legalization above 36 percent.

But surveys also show that there is a persistent perception that alcohol and marijuana are equally harmful and that legalization would merely add another vice.

“This perception is wrong,” says Tvert, “and it can’t be corrected overnight. What we aim for is legislation that would give adults the choice between alcohol and a less harmful alternative. Current laws steer people towards alcohol because they fear the consequences of being caught using marijuana. But I think we are nearing a tipping point.”

Perhaps. One of the biggest obstacles on the road to policy changes is a sprawling bureaucracy of drug warriors who have an obvious interest in keeping things as they are and have long practice in shrugging aside data and evidence. During the eight years of the Bush administration, they were led by a staunch, ideologically-driven proponent of prohibition at any cost, drug czar John Walters.

The man President Barack Obama chose as his top drug policy official, Gil Kerlikowske, is likely to be more open to rational argument. Kerlikowske succeeded Norm Stamper as Seattle police chief and during his tenure, possession of marijuana by an adult ranked as the city’s lowest law enforcement priority. Lower than running a red light.

(You can contact the author at Debusmann@Reuters.com)

(Editing by Kieran Murray)