I hold the non-aggression principle as a tenet of my belief system. For those who may not know what the non-aggression principle(NAP) is, I'll give it to you in a nut shell. The NAP simply states that any use of aggression is illegitimate. By aggression it is meant the initiation of physical force against persons and property, the threat of such, or fraud upon persons or property. The NAP does not preclude the use of violence in self-defense, in this way it is not pacifism.
While I believe it to be ethical to use violence against government agents, I don't encourage anyone to do so. The simple reason is that it isn't effective. When you attack a government agent, other government agents will perceive you as initiating violence against them and will retaliate. Further you will not receive support from the general public because the public at large believes government agents to be legitimate. Harming a single agent, or a group of them, will not change anything other then making other government agents gear up for future attacks.
Government agents in general are sociopaths. Let me explain what I mean by this. 'Mental Health Professionals' state that some signs and symptoms of sociopathy/psychopathy are apparent lack of remorse or empathy for others; poor behavioral controls — expressions of irritability, annoyance, impatience, threats, aggression, and verbal abuse; inadequate control of anger and temper; tendency to violate the boundaries and rights of others; and disregard for safety. There are others, however the 'science' of 'mental health' isn't such a science and so there is room for disagreement even between 'mental health professionals'.
I'd like to take a real world example and examine it closely. Recently a government agent had violence brought against them. I speak of 'Congresswoman' Gabriella Giffords of Arizona. Like I said, I don't believe this violence to be effective however I wish to discuss the issue as a mental exercise.
This government agent took an oath: 'I do solemnly swear (or affirm) that I support and defend the Constitution of the United States against all enemies, foreign and domestic; that I will bear true faith and allegiance to the same; that I take this obligation freely, without any mental reservation or purpose of evasion; and that I will well and faithfully discharge the duties of the office on which I am about to enter: So help me God.'
There exists rules with regards to violations of oath, including definitions and penalties of such. However there is no recourse to seek charges be brought against anyone who violates their oath due the power being delegated to other government agents who refuse to take action because they could lose their job. When all recourse fails there is only one final recourse. Pursuant to the Declaration of Independence, 'that whenever any Form of Government becomes destructive of these ends, it is the Right of the People to alter or to abolish it...'. What does this mean? Government gains its authority by the individuals that comprise it, whenever one of these individuals feels that government has become destructive of its purpose that they can use whatever means needed to alter or abolish it. The use of aggression in this regard will not be effective because government is an expert at the use of aggression.
Back to self-defense theory. Mrs. Giffords violated her oath by supporting further violations of the Constitution that she agreed to. Effectively by doing so she initiated violence against those very persons who elected her to her position. Perhaps there exists some disagreement with this statement, so let me elaborate this concept.
Man A decides for whatever reason, execpt not as an act of defense against the initiation of aggression, hires Man B to kill Man C. Man B kills Man C. Man A is still responsible for Man C's death even if he didn't plan, provide, or execute the death himself. This has been held long within natural law as an initiation of aggression. Let us say that instead of Man C being killed by Man B, Man C instead kills Man B. Man B may have initiated aggression against Man C, but he isn't alone in this initiation of aggression. It should be left to Man C to seek restitution against Man A, should he find out it was Man A as the initiator of aggression. If Man C believes his life is in danger from further attacks by Man A, then it is Man C alone that should be able to determine how this initiation of aggression should be handled, up to and including the use of lethal aggression against him. Personally, I do not handle my business this way, because I do not want others to seek retribution against me for what they may has perceived as an initiation of aggression on my part.
In the case of Mrs. Giffords, she is Man A. In any rule supported by Mrs. Giffords, she is acting as an initiator of aggression. She may not command the rule enforcement officers(Man B) directly that actually cause harm to people(Man C), but without her support the rule enforcement officer would not succeed to cause harm to people(Man C).
I do not condone using aggression against Mrs. Giffords, or her agents, for several reasons, even though I believe it may be an ethical response to their initiation of aggression. The greatest reason of all is that the death of a single agent, or even all the government agents, will resort in continuation of their policies by others who will step up behind him and take the reins, for as long as a majority of people support the system of government as it currently exists. It won't lead to more freedom, and in fact as history has shown leads to more tyranny as we have seen government agents already discussing how they will limit the freedoms of everyone so this is less likely to happen. These actions will not stop it from happening as we have seen if someone is willing to do something, they will generally find a way to do it.
So how should we handle these government agents? There is no easy answer to this problem. Any answer can not use aggression because it isn't effective and will result in the death of those using aggression. Informing people is the first step. If people don't see or understand the problem, then they will never see a problem. It is a small number of folks who are trying to do this. Another way to attempt to solve the problem is to direct the information at the enforcers themselves. However, this won't be as effective due in part to the fact the enforcers are selected based on their ability to be sociopathic to be molded into what government agents want them to do. Even when it was 'legal' to shoot run away slaves, most enforcers gladly killed these people. The Nazi troopers had no qualms in killing Jews.
After the large and difficult problem of informing people of the NAP, the concepts of freedom and liberty, it would be possible to reform the system. Personally I'd only like to see the system reformed only so much as it would allow for the greatest freedom possible. To that end, I'd like to see the success of developing Panarchy so that everyone can have the type of government that they want to have.