To be quite brief, laws are made because we have government, and laws are needed because we need government. The ideas of law and government are dependent upon one another, and I will characterize their relationship in time. For the present it is my task to explain, by Locke's great scholarship, why we need government.
"Man is by nature a social animal." - Aristotle
It has long been the occupation of philosophers and politicians to explain why we find ourselves in a state of association with one another that can be termed "government." Aristotle began with his determination that man is, by nature, a social animal, made to live in association with other men. That philosophy has been revised, built on, and rejected by other philosophers for millennia, but it has endured.
In modern philosophy (and by modern I mean that emerging from the 17th, 18th, 19th, and early 20th centuries) the idea became one of the most substantially dissected topics. Hobbes and Locke, in particular, erected detailed theories of the pre-modern or "theoretical" man and how and why he came to be a part of society living under a government. They termed this man as being in a "state of nature," and attempted to determine and describe his characteristics in this situation. These theories are immensely interesting and all have a direct bearing upon our topic today, so I will give a rough outline of their positions.
1. Thomas Hobbes:
Hobbes is probably the best known theorist to address "the state of nature." As he famously wrote in the Leviathan, man's life in the state of nature is "solitary, poor, nasty, brutish, and short." The most fundamental characteristic of man, he claimed, is the intense fear of violent death. Because nothing rules man moreso than this fear, the state of nature is absolutely hellish. Other people are important only because they represent the danger of violent death. Everywhere around the natural man there is war, terror, death, and uncertainty. Without government, he is on his own. He can rely only on his own physical power and cleverness to secure his life, but even a incomparably strong or clever man can have no rest, for what he lacks in brains and brute another most surely has. His moral power is absolute; he is justified in doing whatever necessary and possible to preserve his own life. This power, as absolute, extends to everything and everyone in his environment, including other people.
When two men meet in the state of nature, both are entitled to kill the other. Whoever is more powerful and/or cunning will succeed and preserve his life, but the uncertainty of what will happen next torments him. Because of the hellishness of it all, man is desparate to escape the state of nature, and is willing to do whatever it takes to secure his life. He gladly enters the social contract by transferring all of his absolute moral power to the executor of the contract (government). Whoever receives the transfer of that absolute power is now entitled to the utmost of tyranny, so long as he preserves the lives of his subjects (for the most part). This is the nature of the social contract under Hobbes: the governed says, "you protect my life from these other people, and in return I will give you absolute power over me." He says to his fellow subjects, "I won't do this unless you do it also." As long as the governor provides stability and safety and the governed obeys, the contract is upheld.
Under this theory, then, man is anti-social, pre-political, and all-powerful in the state of nature.
2. John Locke:
Locke's interpretation of the state of nature is more complex and positive. The state of nature is one of utter equality and freedom. Each man has the freedom to act and do with his possessions whatever he wants "within the bounds of the law of nature." This last phrase is crucial to Locke's understanding. It is his introduction of the notion of law, which Hobbes does not recognize in the state of nature. Locke holds that Divine Law is eternally present, and that the natural man is not only the "workmanship of one omnipotent and infinitely wise Maker," but that he is equipped with reason sufficient to discover and apply the Divine Law. This, the mixture of Divine Law and man's reason, is natural law.
The natural man, then, has power only over himself, to order his own actions, but even that power is not absolute. The reason for this is that man does not own himself - he belongs to God. The taking of one's own life, then, is just as unjust as the taking of another's man's life. Violence of this kind is justified only in the case of self-defense.
The natural man is also not justified in taking or harming another's possessions, for he has power only over his own. He is capable of enjoying and being contented with his environment. Nature offers plenteous fruits and provisions for him, and by the application of his reason, he can make them even more suited to his use. This, the mixing of his creativity and labor with something in his environment, amounts to property. This natural man finds other men not to be inherent enemies, but potential partners. He may interact socially by cooperating, whether through labor or intellect, with other men. Trading is also possible and beneficial to him.
He may be solitary, but his is not anti-social. He is pre-political, but he is not all-powerful. He differs greatly from Hobbes's natural man.
This may sound a bit like the Garden of Eden, but it does break down. The reason is that men are selfish and have imperfect reason, and though each has power only over himself, he is wont to behave aggressively and wrongly towards other men. The Hobbesian moment, therefore (the moment in which a social contract becomes necessary) is when man fears for either his life or his property. For Locke this appears to happen primarily after the introduction of money or currency into the state of nature. Currency makes it possible for men to accumulate more than they need. It seems to awaken the greed which prompts men to act out against each other.
So the situation breaks down anytime a man becomes aggressive towards another's life or property. The state of nature is no longer sufficient in this circumstance because, without an impartial judge or authority, the state devolves into one of war in which men have no recourse but violence. Man is willing, at this point, to enter into a social contract.
When he enters into this contract, he relinquishes some of his power and freedom to a government. Unlike Hobbes's government, this government is limited. The Lockean natural man does not have absolute power, so he cannot transfer absolute power to the government. There is no circumstance under which absolute government is legitimate, therefore, as God is the only being to have absolute power.
Man has three types of powers in the state of nature: the legislative, the executive, and the federative.
1. legislative: The legislative authority consists of deciding how to act. When man enters civil society, he concedes his power to do whatever he wants. He has abandoned license, not freedom.
2. executive: This is the authority to act on the legislative power. When man enters civil society, he gives up the right to execute natural law on his own. This is why lynching is wrong.
3. federative: The federative power is basically an emergency power. It is the authority to act in self-defense in a crisis situation. This power is retained by every man who enters civil society.
Government, having been trusted with the legislative and executive powers, is responsible for making Civil Laws that mirror Divine Law and enforcing or executing those laws in a way that protects each man's right to life, liberty, and property. It has the power to do no more and no less. Government does not exist apart from its responsibility to do these things.
As you can see, Locke's explanation heavily influenced the American Founders, for although their political philosophy differed from his on many particulars, his framework was the one on which they built our government. Unfortunately today we have a government that seems determined to undo it all and write the story along Hobbesian lines. It is our duty then to study these things and understand them so that we can protect our heritage as well as our future.
"If men were angels, no government would be necessary." - James Madison
Recommended reading (and sources of this article):
Leviathan by Thomas Hobbes. It is a long, difficult book, so I recommend starting with these excerpts: Part 1, chpts. 6,8,11,12, 13, 14
The Second Treatise of Civil Government by John Locke. A good place to start is with the sections "The State of Nature," "The Social Contract," and "The Legislative Power."