When we want to decide if a particular substance should be legalized, by which I mean the substance is not entirely prohibited and is available to non-professional recreational users, the first enquiry should be into whether or not people will come to harm as a result of the drug being made available. But this assumption rests upon an initial normative ethical decision where we ask on what grounds a government or legal entity should be entitled to prohibit certain substances by use of force and coercion. John Stuart Mill puts forward two possible conditions which must be met for a government to interfere with someone’s privacy and freedom of behaviour. The first principle is what I will describe as the ‘harm principle’, while the second one is what I will call Mill’s ‘soft paternalism’, which is a practical extension of the harm principle.
Mill argues that the only criteria for limiting freedom of behavior with legal or physical measures are if the consequences of the actions result in harm to another member of society. If a person’s activities do not result in harm to another person then a government has no rational grounds for preventing that behavior, even if the behavior breaks a social taboo. As Mill puts it: “the only purpose for which power can be rightfully exercised over any member of a civilized community aˆ¦ is to prevent harm to others”  . According to the harm principle, then, we would have grounds to legalize drugs as long as we could see no way in which this would result in harm to another person. This means that harm is a jointly sufficient and necessary condition for prohibiting a substance or a type of behavior. If these conditions are not met then we have no rational grounds for making drugs illegal. The practical implementation of this principle means we would be justified in prohibiting a school bus driver from smoking cannabis while driving, as this could result in harm to other people, but we would not be justified in stopping him from smoking cannabis in his own home.
The second condition, which follows naturally from the harm principle, is a condition of soft paternalism. If we are entitled to prohibit types of behavior in order to reduce harm then it follows that harm can befall someone due to ignorance and lack of consent. The soft paternalist stance means that we would be entitled to prohibit someone from taking a drug if they did not know the possible harmful consequences of taking the drug or if they were not of a sufficient metal state to appreciate any danger. If we were to legalize drugs then we would also have to satisfy the sub conditions of ‘consent’ and ‘fore knowledge’, which are jointly sufficient conditions for freedom of behavior along with the harm principle. The practical results of this policy would mean that a government would have no grounds in preventing someone from harming themselves by using drugs which are highly addictive and potentially self destructive drugs such as heroin as long as they consented (i.e. acted on their own free will) to using the drug and had fore knowledge of the consequences. We would only make selling heroin illegal to children or people who were not entirely responsible for their own behavior such as mentally disabled people or insane people. We would also be obliged to make the consequences of taking such a drug clear to the consumer.
The first possible objection to the conclusion of Mill’s argument outlined above is that there are far reaching social consequences to legalizing drugs which the harm principle does not cover. We could consider, for example, the extortionate cost of drug treatment which it could fall on the state to provide. We might also be suspicious that legalizing drugs and making them available on such a wide scale would result in a moral decline and a threat to an orderly civilized community. These objections essentially expose Mill’s harm principle and soft paternalism as being socially myopic. Although drug related behavior which may result in harm befalling people other than the drug taker are a priori undesirable, and that harm is therefore a sufficient condition for prohibiting drug use, it is not the only sufficient condition. It does not follow that, just because individual recreational drug use does not result in immediate harm to another individual, it will not cause havoc if it became a widespread cultural practice. Mill’s argument for justifying the legalization of drugs, his harm principle, cannot be the sole criteria for making ethical judgments. This means that the harm condition may be a sufficient condition for deciding if drugs should be legalized, but it does not mean that it is the sole sufficient condition nor does it mean that it is a necessary condition.
The point to be made here is, I think, that normative deliberations over ethical first principles are inconclusive due to this type of enquiry not being able to really see what the consequences of drug legalization are. We should supplement the harm principle and soft paternalism with descriptive ethical questions, such as ‘what the cost of the war against drugs?’ W.F Buckley Jr. points out the wider social implications of drug taking in a social environment where it is prohibited by law. The fact that drugs are illegal makes them extremely expensive which mean that many drugs users must turn to theft to satisfy their habit, which may ‘require stealing up to $5,000 worth of jewels [or] cars’  . If the fact that drugs are illegal results in a likelihood of harm to other people then it follows that we should at least consider the legalization of some drugs on these grounds. The harm principle, then, must be considered in a wide scope which include sociological and economic considerations such as those pointed out by Buckley.
Another possible objection to the legalization of drugs due to Mill’s conditions being met is that some drugs are highly addictive, so addictive that it constitutes a breech of an individual’s freedom of will. An individual cannot continue to consent to use drugs if he is addicted in an extreme physiological sense to a drug such as heroin. Strong drug addiction does not satisfy the ‘consent’ condition of Mill’s harm principle which means that we should prohibit someone from obtaining such a drug even though he consents to this addiction initially. Soft paternalism would extent to prohibiting the sale of highly addictive drugs in order to protect the individual’s legal and moral autonomy. The harm principle here is too narrow to encompass the unique effects drug taking can have. We must instead rely upon a Kantian understanding of the moral agent, in which we understand a moral agent is an end in itself, and since powerful addiction would violate this, then we should prohibit highly addictive drugs. Kant’s categorical imperative claims that ‘human freedom is realised in the adoption of humanity as an end in itself.’  This means that even though someone consents and has foreknowledge of drug addiction and decides to get himself addicted to drugs his decision is essentially immoral. A possible condition for the legalization of a drug could be that it is not so addictive that it will interfere with an individual’s autonomy or encourage him to act in ways which are harmful to him. If we assent to these arguments there would be no grounds to justify the legalization of heroin while there would be grounds to legalize and permit the use of drugs like cannabis and salvia divinorum which are not highly addictive in a physiological sense.
The problem with this objection can be outlined by clarifying what exactly free will is, i.e. what conditions have to be met for an individual to have free will. Frankfurt defines the freedom of will as being the possibility of having done otherwise  , which means that as long as one’s will is synchronized with one’s actions, one has free will. If you desired not to take a drug and someone physically forced you to do this you would not have free will as you could not have done otherwise. Frankfurt’s position on free will is what I will describe as a ‘coherentist’ position, by which I mean an individual acts freely if his primary intentions coincide with their behaviour even if they are unable to prevent this behaviour. If an individual who is addicted to drugs and is unable to act in any other way because of this then this is still an instance of free will as long as this behaviour coheres with previous decisions made under consent and foreknowledge. A heroin addict is not forced to take drugs even when addicted in the sense that they could have done otherwise. Although his behaviour is determined by the drugs his will is not impeded in the way that brainwashing or direct physical coercion by another person will impede free will. Kane describes the condition of personal autonomy as “the power to be the ultimate producers of [one’s] own end and the power to make choices which can only and finally be explained in terms of [one’s] own [will] (i.e., character, motives, and efforts of will) .  ” If these conditions are met then there is no realistic breech of the consent and foreknowledge and there is no ground to prevent the sale of highly addictive drugs.
We can conclude, in regard to the above arguments, that Mill’s harm principle and the sub-conditions of assent and foreknowledge give grounds for legalizing the sale of drugs as long as these conditions are met. The only grounds on which we could make a drug like heroin illegal is by taking a what I will describe as a ‘strong paternalist’ approach to welfare, in which citizens are prohibited from partaking in activities which will inflict harm of them even though they themselves desire or are aware of harmful consequences. This must be balanced, however, upon the implications of actually making these activities illegal. A strong paternalist approach to car safety is to make it illegal for motorists not to wear seatbelts. There are only positive consequences of this legislation. Making heroin illegal, on the other hand, increases the price of heroin to levels only affordable by serious crime, increases the risk of negative health implications do to unregulated heroin production and includes the risk of people infecting themselves by using unregulated drug taking equipment and diverts money and resources into enforcing these laws at the expense of others.
Lord Devlin, on the other hand, argues against the legalization of drugs considered taboo or immoral in a society from a view point which does not necessarily rely on the negative consequences to individuals or the harm to an individual’s autonomy. Lord Delvin argues, first of all, that any social group posses a right to protect its own existence. He then goes on to argue that particular morals and ethical standards which a community stands by should be enforced to protect the existence of a community. He then concludes that moral standards can be maintained by force and the curtailing of individual liberty. “Society”, he claims, “may use the law to preserve morality in the same way it uses it to safeguard anything else if it is essential to its existence.”  If it could be shown that the legalization of drugs such as cannabis or heroin would contradict moral standards then these “deviations from [the] society’s shared morality …are capable in their nature of threatening the existence of society” and therefore “cannot be put beyond the law.  ” The problem with Lord Delvin’s argument is that it fails to give an adequate explanation as to why a deviation from a routine moral standard is necessarily a threat to a society’s existence. It simply does not follow that if an individual practises certain types of behaviour in the privacy of his own home, such as smoking cannabis, this results in a negative impact to the survival of a society. It also does not take into account that particular customs of a society may have evolved to meet specific needs which is no longer relevant. On the other hand, moral standards may have been enforced due to a lack of scientific understanding. It is certainly true that widespread incest could result in a threat to the existence of society due to genetic diseases becoming more prevalent in society, and it is therefore rational and just to enforce compliance to non-incestuous marriage. But it difficult to see how the legalization of a non addictive hallucinogenic drug with few side effects during moderate consumption could pose any threat to a society’s existence.
To conclude, I will summarize the conditions which should be met for the legalization of a substance to be considered ethically legitimate. It must first of all only be made available to those who consent and have foreknowledge of the consequences of the drug, no matter how addictive or harmful it may be when it is consumed. The results of the consumption of the drug should also have no negative consequences towards society at large. This could mean that a drug which, when consumed, could result in harmful environmental impact or damage to others who are not consuming the drug, should be banned. This could also mean that people are prohibited from taking the drug at particular public locations. It could also mean that the drug is only allowed be consumed at special facilities in which it can be regulated. The practical implementation of this could mean that one would be permitted to smoke cannabis consume ecstasy at particular venues.