"Self defence is a part of the law of nature; nor can it be denied the community, even against the king himself!" ~ John Locke
Civil Disobedience: An Overview of Nonviolent Resistance to the State
For starters, let us define our terms:
civil - pertaining to citizens; humane, considerate, kind.
disobedience - refusing or failing to obey orders.
nonviolent - not using physical force or strength to cause injury.
resistance - the act of opposing or refusing to comply.
State - supreme ruling power of a country.
Putting these definitions together, our topic may be defined as the gentle, but firm, refusal of the inhabitants of a community to follow the political laws promulgated by its government.
Why is this an important subject to readers of Strike The Root? It is significant because, as Gene Sharp has stated:
No government can exist for a single moment without the cooperation of the people, willing or forced, and if the people withdraw their cooperation, the government will come to a standstill . . . . Even the most powerful government cannot rule without the cooperation of the ruled.
When people refuse their cooperation, withhold their help, persist in their disobedience and defiance, they are denying their opponent the basic assistance and cooperation which any government or hierarchical system requires. If they do this in sufficient numbers and for long enough, that government or hierarchical system will no longer have power. This is the basic political assumption of nonviolent action. 
Of course, people may choose to fight the State by employing violence: shooting government agents, throwing bombs, blowing up government buildings, but are they really doing anything to accomplish their goal of ridding themselves of the State? Can the idea of the State be affected by forceful means? No. The State is a state of mind, an idea which cannot be harmed by violence. Ideas can only be attacked with better ideas. What the State idea has claimed for itself over the ages is "legitimacy": the idea that society requires some form of political government to survive and thrive.
It is impossible that the idea of "legitimacy" be attacked with force. Even if an insurgent movement were to be successful in overcoming the military and police of the State, wouldn't the rest of the population still believe that some sort of government was necessary? State legitimacy can only be destroyed when sufficient numbers of people come to view government actions in the same moral light as that of the individual. If this moral leveling is not brought about, if this delegitimization is not accomplished, then violent revolution must inevitably fail, even if it were successful in battle. The destruction of State legitimacy must precede the advent of violent revolution, and when that has occurred, violence against the State will be unnecessary. Under any other circumstances, violent revolution will only result in the replacement of one government by another. (Of course, electoral politics is subject to the same criticisms and questions: How can jockeying for positions of State power via elections possibly delegitimize the State?)
Gene Sharp has defined "nonviolent action" as those methods of protest, resistance, and/or intervention without physical violence, in which members of the nonviolent group do or refuse to do certain things. Sharp has categorized nearly 200 activities, from refusal to pay taxes, mass rallies, marches, and protests, to wearing colored armbands to express one's support of the protesters and one's opposition to the government. Sharp has also cataloged many historical examples of nonviolent actions. Probably the first recorded act of civil disobedience in history is the refusal of the Hebrew midwives to obey Pharaoh's order to kill male Hebrew babies in 1350 BC (Exodus 1:15-19). Their refusal to obey an inherently unjust political law highlights the relationship between conscientious objection, civil disobedience, and nonviolent resistance. The midwives did not intend to delegitimize Pharaoh's dynasty, but neither would they obey a political law which was opposed to the law of God and nature that innocents should not be killed. Hence, their refusal to act against their conscience. But to many readers of these pages, every political law is unjust by its very nature--being a dictate of the State. To anarchists and voluntaryists, if government law directs them to do what is right, they respect the law, not because it is political law, but because what it directs them to do is already right by nature, logic, and common sense. But if the law tells them to do what is wrong, they disobey or ignore it.
Mahatma Gandhi, one of the most celebrated and recognized advocates of nonviolent resistance, maintained that non-cooperation with evil was always a duty, and argued that the performance of duty and respect for one's conscience must always be maintained regardless of consequences. How did the Egyptian midwives know that they wouldn't be killed for refusing to obey Pharaoh's orders? They didn't. How many Russian dissidents knew in advance that they wouldn't be killed or jailed? None. But that did not deter them from doing what they saw as right. As Vladimir Bukovsky, one of them, wrote so eloquently in 1977:
We had grasped the great truth that it was not rifles, not tanks, not atom bombs that created power, nor upon them that power rested. Power depended upon public obedience, upon a willingness to submit. Therefore each individual who refused to submit to force reduced that force by one 250 millionth of its sum . . . .
We weren't playing politics, we didn't compose programs for the liberation of the people, we didn't found unions . . . . Our sole weapon was publicity. Not propaganda, but publicity, so that no one could say afterward, "I didn't know." The rest depended on each individual's conscience. Neither did we expect victory--there wasn't the slightest hope of achieving it. But each of us craved the right to say to our descendants: "I did all that I could. I never went against my conscience." 
Such a stance against the Soviet regime, which at that time seemed impregnable, may appear to have been foolhardy, even insane. However, as Leo Tolstoy noted, those who choose to resist, "have only one thing, but that is the most powerful thing in the world--Truth." And in the truth of nonviolent resistance we find the following pearls of wisdom:
"[T]he prim[ary] human obligation is to act fearlessly and in accord with one's beliefs; that one should withdraw cooperation from destructive institutions; that this should be done without violence . . .; that means are more important than ends; that crimes shouldn't be committed today for the sake of a better world tomorrow; that violence brutalizes the user as well as the victim; that the value of action lies in the direct benefit it brings society; that action is usually best aimed at one's immediate surroundings and only later at more distant goals; that winning state power"  should be eschewed; that freedom begins with one's self because freedom is self-control; that freedom is oriented toward a love for truth; and that all power depends upon the consent of the governed.
~ Carl Watner, January 2010
 Gene Sharp, THE POLITICS OF NONVIOLENT ACTION, Boston: Porter Sargent Publishers, 1973. From Part One, "Power and Struggle," p. 64.
 Vladimir Bukovsky, TO BUILD A CASTLE - MY LIFE AS A DISSENTER, New York: Viking Press, 1977, pp. 33, 277.
 Jonathan Schell, THE UNCONQUERABLE WORLD, New York: Metropolitan Books, 2003., p. 201.