When I was an MP I agonised over the justice, liberty  and efficacy issues in drug laws, including alcohol. I stopped ACT becoming the ‘decriminalize cannabis party’ but only because the cannabis liberals never managed (or even tried) to explain how they were going to prevent even more cannabis damage to children if the Police had no practical way to threaten adults who supply it.

I was concerned also to know how we would enforce law against driving/working while stoned. Harms to third parties are legitimate considerations for classical liberals. Nandor and Co were silly enough to protest against employer and teacher rights to stipulate their own rules and random testing and inspections. It was clear that they did not care about collateral damage, so it was never hard for me to avoid having ACT branded as inconsistent, at least with people who were knowledgeable about classical liberalism since JS Mill.

I also worried that while we retained a ‘non-judgmental’ welfare system it could support stoners into much higher than natural levels of dependency. Even natural social constraints are not proof against mass dopiness. An opium epidemic shocked the Chinese Emperor into banning British opium exports nearly two centuries ago. Even if Darwinian wisdom might let society reach its equilibrium level of stoners, those at the margin (or their parents) could reasonably object that there was a much higher than natural proportion of the population made vulnerable when the welfare industry hoovered up the natural evidence of what a loser's life it was, at the tax expense of workers made of sterner stuff.

From my observations in several poor countries where cannabis was freely available, it was unattractive to locals because their culture reflected the survival need for people to have all their wits about them. They could not afford to be addled. But there seemed to be no prospect of ensuring that stoners here were made personally responsible for their own support.

Now we desperately need some principled debate in favour of freedom and personal responsibility.

My firm is fighting right now for child sexual abuse victims to be allowed the right to “harm themselves” by ending name suppression for the criminals who have hurt them. The suppression is allegedly in the victims' interests. In reality that is just an excuse for insiders, courts and officials,  to keep exercising their powers over others. The 'protection' has been hijacked for their satisfaction and the benefit of  wrong-doers.

So we are pushing for genuine respect for personal freedoms, whether or not the powerful think it is in the victims’ best interests.

There are plenty of good reasons to challenge the criminalisation of suppliers of goods not proven dangerous (and even those that are plainly dangerous – like alcohol) to willing adult buyers. Supply offenders are not 'victimless', because drug users are losers. But the ‘victims’ seek out the ‘offenders’.

A tenet of liberty is that the state's coercive powers should not be used to limit the freedom of informed adults. For years we struggled to get rid of the laws that enforced only a censorious majority's opinion of what behaviour was self damaging. Laws against homosexuality, breaking marriage vows, abandoning your responsibilities to support children and aged parents and many other 'moral offenses' have been repealed. The slogan 'the law has no place in the bedrooms of the nation' reflected a view that minorities should be free of majority tyranny.

It will be interesting to see if any National Party MPs dare to distinguish their position on these drugs from freedom to ride motocross, or play polo, or climb mountains, or play rugby, or not wear a helmet on your quad bike? Why applaud nanny state banning of this one form of self harm but have no law against eating too much or drinking  to drunkenness, or giving yourself diabetes with soft drinks, or any other of the myriad  ways people harm themselves.

Some of those harms are much more expensive (in terms of the numbers who are susceptible) and with more proven cause/consequence connection.

And where does this take National's concern about the cotton wool society? How will any argue to end punishing employers for risks willingly incurred or even embraced by employees? Where is National's end point to the powers of the state?

Supporters of the ban talk of young people and their families having been been destroyed? Perhaps. But who has established that the same young adults would not have found another way to harm themselves (alcohol?) and perhaps other people at the same time. If these drugs are the current generation’s form of rebellion, and the law works to end supply, is there any reason to believe that the chosen alternatives will not be more dire?

The Coca Cola bottlers and chocolate manufacturers and wine-growers and deep fat frying businesses should take a deep interest in this debate. The same harm principle could fix them with overnight punishment for sale of their legal poisons.

At the very least a National government that claims to protect property rights should be promising to compensate the suppliers for the stocks they have bought in reliance on the recent law that expressly legitmised their stocks.

There would be no reason to claim fears of stock-piling and panic buying if the principled step had been taken – of promising to buy the existing stocks at some point between cost and retail that left the suppliers without losses.