Government's job is to protect (individual) rights.

What is the purpose of government under capitalism?
It is to protect rights that governments are instituted. A proper government's only responsibility is to protect the rights of the individual, by banning the initiation of force, thus making all relations between men peaceful, i.e., free from the threat of violence and fraud.

What do you mean by the initiation of force?
In a political context, freedom has only one specific meaning -- freedom from the initiation of force by other men. By initiation I mean those who start the use of force to achieve their ends, i.e., a bank robber. Only the initiation of force against a man can stop his mind, thus rendering it useless as a means of survival. Only by the initiation of force can a man be: prevented from speaking, or robbed of his possessions, or murdered. Only through the initiation of force can a man's rights be violated.

What do individuals delegate to government?
In order to place the retaliatory use of force under objective legal control -- that is, under clearly defined laws that are logically deduced from the principle of rights -- those who make up society delegate their right to retaliate against those who initiate force, to government.

What is the purpose of law?
In a free society each and every man lives under a rule of law, as opposed to a whim-ridden rule of men. Such a rule of law has only one purpose: to protect the rights of the smallest minority that has ever existed -- the individual. Such laws form objective legislation, which hold a man innocent until he can be proven guilty, as opposed to a library of irrational regulations which hold a man guilty until he can somehow prove himself innocent, to the gratification of some Atilla able to gain a foothold in public office. In a free society it is the actions of government -- and not the actions of citizens -- that are regulated.

What is the purpose of the constitution?
To ensure no despot -- whether that despot be a single dictator, an elite political pressure-group, or the befuddled democratic majority of the moment -- may usurp the powers of government, and turn its machinery upon its citizens, each and every aspect of government action is codified, and carried out, according to objectively defined laws. The supreme legal document of a proper society is the constitution -- a citizen's protection not only against private criminals, but public ones also.

What would a society be without government, i.e., without the delegation of the use of force?
Man's state in nature, where every man is allowed complete discretion in the retaliatory use of force, according to the laws of the jungle, is nothing more than a state of anarchy -- perpetual civil war and gang warfare. If there were no legal agency to carry out such a task, each man would be forced to carry out retaliation at his own discretion, i.e., anarchy. A modern day example of such a situation is Bosnia, where two gangs, or "competing governments" -- the Croats and the Serbs -- are competing with each other in the same geographical area. So much for the libertarian-anarchist version of a "free" society -- a society where everyone is free to murder.

Can men use force in self defense?
To use force in retaliation -- in self defense against those who initiate it -- is not a moral option, but a moral requirement. A moral man has nothing to gain when a man tries to kill him, but he has much to lose if he does not defend himself. For this reason it is right, just, and proper to use force in retaliation and self-defense. The use of force, in and of itself, is not evil -- but to initiate (start) force is. Contrary to the vile doctrines of the pacifists, force used in self-defense is a species of the good.

Does government's monopoly on the use of force give it the right to initiate (start) force against others?
Under no conditions may government violate anyone's rights, by initiating force against others. A proper government is permitted to use force to retaliate against a thief who has initiated force against someone (in the act of robbing them). However, a proper government is not permitted to copy the means of private criminals by initiating force against its citizens. The government is not even permitted to rob them of their wealth--even, or rather especially, if the stolen loot is to be used for so called "noble" purposes, such as for the sick and poor. No end (even for the "poor") ever justifies an illegitimate means (the initiation of force). Any man who initiates force against others is a dictator, and should be treated as such, to the extent he initiates force.

Can citizens delegate the right to initiate force to government?
Citizens may not delegate the "right to initiate force" to government, as no one possess such a "right" to begin with.  As Ayn Rand has commented "there is no such thing as the right to enslave." What individuals do possess is the right to defend against force (in some cases this may include pre-emptive action). As no individual in his private capacity, as a citizen, may initiate force against others, neither may he in his public capacity as a state official initiate force either.

Doesn't the cause of the "public good" justify the initiation of force?
No one may initiate force for any reason whatsoever, even if that alleged purpose is for the "public good". For is not the individual whose rights are being violated for the "public good", a member of the "public" also? How can such a violation be in the public's good? For is not his good also the good of the public, of which he is a member? The truth is, such violations are only in the irrational interests of a division of the public, but are not in the interests of the entire public.

How does government carry out its' duties in practice?
To protect rights, government require essentially three things: an army -- to protect against foreign invaders, a police force -- to protect against domestic criminals, and a court system -- to settle honest disputes that arise, and to punish criminals according to objectively predefined laws.