Cocaine controversy ... A British TV show with broadcast people taking Class A drugs.

Cocaine controversy.

Conservatives are starting to adopt a more liberal stance on the narcotics campaign.

IN 2011, the war to end the war on drugs is now being led by conservative voices, not radical ones. In March, three federal Liberal backbenchers - Mal Washer, Judi Moylan, and the Victorian Russell Broadbent - came out against the criminal status of drug use, going so far as to argue that heroin and cocaine should be legalised. Dr Washer described the war on drugs as a ''crime against humanity''.

Indeed, those Liberals have been more vocal than the apparently radical Greens, who abandoned their support for drug decriminalisation after they found it brought more controversy than was comfortable.

And the backbenchers join a global phenomenon - conservative voices coming out against the drug war.

Last month the Global Commission on Drug Policy concluded that drug prohibition has been an abject failure. The panel includes Sir Richard Branson and Nobel laureate in literature Mario Vargas Llosa. Both hold right-of-centre economic views.

Two commission members, one a former US Secretary of State, the other a Federal Reserve chairman, had their argument featured on the conservative Wall Street Journal opinion page.

Little has changed in a practical sense, only that the pointlessness of the approach to drugs has become even more obvious over time.

Julia Gillard and Tony Abbott have admitted using marijuana when they were young. So have Malcolm Turnbull, Wayne Swan and Peter Garrett.

This would all be harmless fun but for one thing. Last financial year, according to the Australian Crime Commission, 57,170 people were arrested in Australia on marijuana-related charges - a drug that Australia's most senior politicians happily admit to having used.

Their confessions are typically made with a sheepish grin, followed quickly by a stern parental admonition - ''It was a mistake to do so,'' said Malcolm Turnbull. Julia Gillard: ''Tried it, didn't like it. I think many Australian adults would be able to make the same statement, so I don't think it matters one way or the other.''

Well, it would matter if you were one of the almost 60,000 Australians arrested for holding, consuming, or supplying cannabis to aspiring politicians last year.

In Australia, marijuana is treated with a degree of leniency, at least compared to other drugs.

Nevertheless, Australian police made more drug-related arrests last year than at any time in the past decade. And about 20 per cent of Australians report having used an illegal drug. These are not the typical indications of policy triumph.

Outright prohibition has been no more a success at reducing the harm caused by drug use in the 21st century than alcohol prohibition was in the 20th.

Melbourne's cycle of gang warfare has been fuelled by the illegal industries that have grown up around prohibition. In 2001, Portugal decriminalised everything from marijuana to heroin. Drug trafficking remained a crime, but possession and use became nothing more than administrative violations. Providing drugs to minors remained illegal, as did providing drugs to people with a mental illness.

According to a study by the Cato Institute, an American free-market think tank, the results of this experiment have been positive. Drug use didn't go up, contrary to the nightmare scenarios predicted - particularly among 13 to 18-year-olds.

This is unsurprising. As a product comes out of the illegal underground, it is easier to regulate, control and manage. Cato found that almost every single measure of progress - HIV rates, drug-related mortality - had gone down since 2001.

Obviously decriminalisation is very different from full legalisation. The latter would be an understanding that individuals had the right to ingest whatever they liked. The former balances the criminal and the individual responsibility approaches.

Portugal chose to decriminalise because they didn't intend to normalise or encourage drug use. And none of the conservative voices who have joined the chorus against the drug war are pro-drugs.

But Portugal's strategic retreat has done more good in its 10 short years than 30 years of criminalisation. The United States, which has the harshest penalties for drug possession, also has the highest levels of cannabis and cocaine consumption.

Portugal's model is one Australia could - and should - adopt.

Unfortunately, governments get easy political mileage out of looking tough on drugs. Ted Baillieu wants to crack down on the sale of the bongs - an entirely symbolic gesture - but one that apparently resonates with a certain type of voter.

And social reform can take a long time. One of the intellectual heroes of the free-market movement, Milton Friedman, called for an end to the war on drugs way back in 1972.

Yet conservative scepticism about the criminal approach to drug use is spreading.

If both sides of politics are starting to doubt the wisdom of the drug war, there's a chance - a chance - we may eventually take Portugal's lead and call a ceasefire.

Chris Berg is a research fellow with the Institute of Public Affairs,