What makes the state legitimate? Is the state justified on the grounds that it provides public goods? Do goods provided by the state outweigh restrictions placed on individual liberties?
If the state is characterized as at best a necessary evil, then we must justify its existence by demonstrating that we do indeed need it. The state will inevitably infringe upon our freedom to do as we will, so in order for us to feel that such infringements upon our liberty are legitimate, we must accept that the state has some legitimacy. If the state could be seen as a provider of some good (that would not otherwise be provided in the absence of the state), then perhaps this would render the state and its liberty infringements legitimate.
Do we need it to maintain peace and order, or to protect our society from foreign terrorists? Is it necessary to protect the environment or to maintain the necessary conditions for the market to function? These needs are satisfied as public goods, because they are not consumed by individuals. They are consumed by the public. The free exchange of goods in the market can efficiently distribute private goods because private goods such as a pizza are consumed by private individuals. However, a public good is consumed publicly. According to Michael Taylor, “A good is said to be public if it is characterized by some degree of indivisibility or ‘jointness’ of supply, that is, if consumption of any unit of the good by any member of the public in question does not prevent any other member of the public from consuming the same unit, or if, equivalently, any unit of the good, once produced, can be made to every member of the public.”