If the state has the power of life and death over its citizens, and if we accept that, at least under specific circumstances, this power is even legitimately exercised, we are left to determine the limits of this use of state violence. In Chapter 2, I have already argued that there is an internal restriction to the legitimacy of violence. Any use of violence needs to be proportionate to the perceived threat and the ends to be achieved. Violence may be used, I argued, to oppose other types of violence, and in particular when the safety and security of those involved is threatened. But the use of physical and moral force is also limited externally – that is, by reference to another important concept of political thought: liberty.

Two liberties

In 1819, Benjamin Constant (1819/2010) proposed to introduce a recent distinction between two types of liberty. The ancients, in a few words, considered liberty to be the ability to rule over a common polity collectively, to legislate and judge, to condemn and absolve. But, as Constant points out, this collective liberty was not only compatible with, but dependent on the subjugation of the individual to the collective body. The collective body was free, but the citizen had to be subjected to its judgement. The most iconic example of such subjugation is the acceptance by Socrates of the death sentence assigned by his peers. Socrates felt compelled to accept his fate, and refused the opportunity to turn against his city and flee to save his life (Plato, 2003). By contrast, the liberty of the moderns, which is still our form of liberty today, is concerned with the fate of the individual. Liberty, since the rise of the modern state and its political institutions, is about freedom from arbitrariness (even from the arbitrariness of the collective), choosing one's path in life without restrictions, expressing one's opinion without fear of repression, and generally being limited by laws and rules rather than the will of those in power and their particular dispositions. This liberty, interestingly for Constant, is first and foremost a private enjoyment rather than a public good. Whereas the ancients thought that liberty was linked to a group's ability to rule over itself and make political decisions, for Constant the modern individual wants to be as free as possible from making political decisions in the first place.