What exactly is a "libertarian"? A libertarian is a person who practices "libertarianism"; who believes in and lives by the Zero Aggression Principle (the ZAP); sometimes known as the Non-Aggression Principle, which states:
"No human being has the right -- under any circumstances -- to initiate force against another human being, nor to threaten or delegate its initiation."
Committing theft or fraud also falls under the ZAP as these are forms of force; they take what you have worked for with your own time and labor away from you against your will or under false pretext. Can you see how "taxation" fits in here as well?
Many, if not most, of the criticisms of libertarians I have read revolve around how the ZAP is interpreted. Some critics argue that libertarians are pacifists. Others argue that one or more core concepts of "The State" are good or "necessary evils". Still others claim that libertarians will strike out and kill anyone who angers us using the excuse that the other person initiated force. On the other hand, anyone with a functional intellect can see and understand when force has been initiated. Carrying a gun in your holster is not initiating force, even if a hoplophobe sees it and has a panic attack. Pointing that gun at a person who is making an obscene gesture at you in traffic is initiating force. Taking a person's property from them while implying that there will be consequences if the person does not comply is initiating force. Asking for a donation is not. The critics just don't get it and are not thinking. They ignore the word "initiate" in almost all cases. Probably intentionally, since they have no other argument.
I have also seen ("left") racists attempt to turn the tables by calling libertarians racist. A racist is someone who makes an issue of race. Libertarians do not do this. Socialists and other authoritarians do. Their philosophy depends on making people angry at one another. That is where they get their power.
A libertarian may or may not be a member of the Libertarian Party. This is the distinction between what is called a "big 'L' Libertarian" and a "small 'L' libertarian".
Then there are the anarchists and the minarchists. Both may consider themselves a type of libertarian. I am proud to be an anarchist libertarian. "Anarchy" means "no rulers". The definition of "anarchy" has been corrupted to be understood as "no rules; chaos". There is a big difference between "no rulers" and "no rules". "Minarchy" means "minimum rulers". Few people have ever heard of "minarchy" so the definition hasn't had a chance to be corrupted yet.
Some people believe, as I do, that government is not possible (or necessary) within a pure libertarian society. These are the "anarchists". Government is built upon coercion and theft: the people who live within its sphere must do what the government demands or some form of punishment will be forced upon them. Government takes money from the people by a special form of theft called "taxation". If it were not theft, there would be no punishment for not paying and it would be completely voluntary. Some people believe in what is known as "minarchism". They think it is possible to have a tiny, weak government which will provide for regional defense, punish those who violate the ZAP, and maintain roadways within its sphere of influence. How will these functions be financed? How would the roadways be built without taking land from someone against their will?
At the other end of the spectrum are the "authoritarians". Authoritarians seek to control others, through either government force or freelance crime. Authoritarians who approve of government force and believe that "government is a legitimate human endeavor" are known as "statists". Authoritarians are the people who normally seek "public office". They believe that people must be controlled. They believe in such concepts as "the public good", "social contracts", and "implied consent". Authoritarians do not believe you have the sense to run your own life, as they believe that people are weak and stupid. Yet they seek power over your life while demonstrating time and again that they are no more intelligent than you are. If people cannot be trusted to run their own lives, how can they be trusted to run the lives of others? Who knows what is best for you? Some person in a far away government office, or you?
In short, libertarians acknowledge that YOU own your life. They recognize that you know what is best for you, and that you can achieve your best without preying on anyone else. If you wish to live under the control of authoritarians, that is your decision, but you have no right to impose that choice on anyone else. Unfortunately this is where the conflict arises: authoritarians can not allow anyone to live unmolested. They invariably initiate force against people whose only crime is wishing to be left alone. Once that line has been crossed and force has been initiated, force may be used legitimately by libertarians in defense of their lives, liberty, and property. This is what the Declaration of Independence was all about. Ask yourself the Shorty Dawkins questions: "Would the founding fathers be proud of the government and society of today? Do you think they would revolt again?"
The Political Hierarchy Chart
"Political tags-such as royalist, communist, democrat, populist, fascist, liberal, conservative, and so forth-are never basic criteria. The human race divides politically into those who want people to be controlled and those who have no such desire." -- Robert A Heinlein
I designed this chart to show the relationships between the various political philosophies. As you pass from freedom at the top, through apathy in the middle, down to the authoritarians (those who wish to control or punish others) on the bottom, you pass through all of the ways that people relate to one another. It is obviously not "to scale" as I think that "apathy" would dominate the page if it were, and that the "authoritarian" bubble would also be much larger. This should be a 4-dimensional chart, with the top and bottom meeting in a loop to be connected by another line, and with different areas growing or shrinking over time. I would need a holographic video to properly illustrate this. I feel it is possible to jump from one area to another, but is more likely that movement will be between adjacent areas. Political power would probably be wielded by the largest "non-apathy" area, but could possibly be held by the most vibrantly active area instead.