In much of the world today, a similar proportion of pregnancies end in abortion as the fraction that in centuries past ended in infanticide… If abortion counts as a form of violence, the West has made no progress in its treatment of children. Indeed, because effective abortion has become widely available only since the 1970s… the moral state of the West hasn’t improved; it has collapsed.
- Stephen Pinker, The Better Angels of Our Nature
Worldwide, 73 million abortions take place annually. That is equivalent to the total deaths of the Second World War, taking place every single year. Over a third of all innocent children that start life in the modern world are killed by abortion.
Given these numbers, this single issue surely represents the worst violation of the nonaggression principle in our times. It is far worse than any government program. It is a more egregious violation of the nonaggression principle than war, taxation, or fiat currency. Yet libertarians not only fail to criticise it, they actually provide moral sanction for this practice.
If libertarians argue that abortion is justified, they cannot object to any particular motive for abortion. They cannot object to the extermination of children with down syndrome for eugenic reasons. They cannot object to the extermination of girls for misogynist reasons. From 1970 to 2010, approximately 105 million females were missing in China and India due to selective abortion. Their own logic compels libertarians to view such practices as perfectly legitimate.
In the late nineteenth century, the leading classical liberal thinker Herbert Spencer pointed to the improved protection of the rights of children as a sign of civilisational progress:
Thus an extreme contrast exists between those early states in which a child, like a brute, could be killed with impunity, and modern states in which infanticide is classed as murder and artificial abortion as a crime, in which harsh treatment or inadequate sustentation by a parent is punishable, and in which, under trust, a child is capable of valid ownership.
- Herbert Spencer, Principles of Ethics (1888)
Spencer specifically listed the criminalisation of abortion as one of these signs of civilisational progress. It is notable that this was such an obvious argument at the time that he felt no need to justify it. He saw abortion as a blatant and straightforward violation of the nonaggression principle.
In the twentieth century, abortion was decriminalised and there was a widespread cultural shift from abhorrence to acceptance. Libertarians not only went along with this moral and cultural change, they led it. In doing so, they did immense damage to libertarian theory.
Not only is support for abortion incompatible with libertarian theory, it is arguably the worst thing that libertarians could possibly choose to support in present times.