During the year 2006-07, India is reminding itself of the epochal contribution Mahatma Gandhi made a century ago in 1906 to give in the hands of the weak, whether individuals, or groups or nations, a new weapon to fight oppression and injustice.  The weapon was Passive Resistance later renamed as Satyagraha.  In recognition of this gift of Gandhi to humanity, the United Nations has declared October 2, the birth anniversary of Mahatma Gandhi, as the Day of Nonviolence.
Gandhi's mission was not without obstacles.  It was difficult to convince people that soul force could subdue brute force not by defeating it but by melting it into a love force.  That apart, a number of men and women in public life, including some of Gandhi's own colleagues argued against it.  Even today there are people who think that Satyagraha might have been good to fight a colonial government but it has no relevance in a democratic set up, irrespective of cause.
When Gandhi pitched his soul force against the brute force of the British Imperialism, he had no bitterness against the British people; he rather loved them as he loved his own countrymen. But he was against the British Raj for it was imposed on India against its will and it brought untold miseries to the people.  His offensive, even if nonviolent, began in South Africa in 1906 and ceased in India in 1948 not because his goal was achieved but because he was assassinated by the very people he loved so enormously and for whose transformation he worked incessantly.

It was June 7, 1893 and the place was Pietermaritzberg in South Africa, a small railway station on the way from Durban to Johannesburg.  Barrister Mohandas Karamchand Gandhi was thrown out of a train unjustly and illegally. His fault: he dared to travel in an upper class compartment reserved only for the 'whites'. He spent the cold night musing over the fate of millions of people who were treated worst for the only fault that their skin was 'coloured'. Gandhi experienced a deep spiritual awakening within him and decided not to rest until the discriminatory treatment against Indian settlers by the then South African government was ended.
Gandhi decided to fight against the injustice done to him and to masses of people in the name of 'civilization'. He launched a movement designed to oppose the wrongdoings of the whites of South Africa against the Asians and Africans.  He called for joint action without the use of violence.  Since violence breeds violence; the fight must be cooperative and nonviolent.  And the fight must be against the injustice, not against those who perpetrated injustice. It was decided to oppose all discriminatory laws and rules.  But the movement must remain nonviolent.  The movement came to be known as non-cooperation movement.  By 1911 it was renamed as Satyagraha and made more comprehensive and philosophically sound.
Satyagraha demanded complete dedication to truth and nonviolence and this was possible only if the life of the person practicing it was pure and simple.  In order that he is not afraid of losing anything, he should not be attached to anything but truth and nonviolence.  It was September 11, 1906, when he put his concept of Satyagraha in practice on a scale he had not done before and opened the path of nonviolent mass movement.
I prefer to call Satyagraha as 'a weapon of war' because Gandhi unleashed love towards his opponents with such a great fury that they, being human beings, had no choice but to give in. 
Satyagraha has been criticized as an impractical exercise.  Questions were and are being raised about the relevance of Satyagraha in a fast changing world. No one could have stopped India from gaining independence by resorting to violence.  But if what is happening in our neighbouring countries, which gained independence by fighting a violent war, one doubts if India would have remained united and democratic had it not got its freedom the Gandhian way.

After Mahatma's death many of his followers tried to mould satyagraha to solve the problems of democratic India. Vinoba Bhave laid down four principles of satyagraha in 1958 to make it consistent with democratic India:
1. It must be positive;
2.  It should proceed from gently, to gentler and finally gentlest;
3.  The very word Satyagraha should arouse happiness; and<
4.  There should be no insistence on the part of the satyagrahi; insistence should come from truth itself.
Jay Prakash Narayan had spent most of his life as a major actor on the political stage.  He joined Vinoba, and dedicated the rest of his life to Bhoodan and Sarvodaya.  After sometime he launched a satyagraha called Sampoorna Kranti but he removed from it the otherworldly underpinnings.  He tried to become Gandhi-the-politician minus Gandhi-the-saint. Besides these two there were others who took up causes ranging from the Chipko Movement which was launched by Chandi Prasad Bhatt and popularized by Sunderlal Bahuguna to protect the forests, Medha Patkar's movement for the rehabilitation of Sardar Sarovar Dam oustees in Gujarat, to Mamta Banerjee's movement against SEZ in Nandigram in West Bengal.  All these constitute a form of Satyagraha chiseled to specific social political and economic contexts.
Not only in India, civil society all over the world on many occasions organized peaceful sit-ins and demonstrations to impress upon various international agencies and national governments to save the earth from getting barren and to change their ways in favour of the poor and deprived masses.

Despite global recognition of satyagraha as the ultimate way of conflict resolution, its critics have not been scarce.  There are people who reject it on the ground that violence has a cleansing effect when the oppressed rise against their oppressors.  Plenty feel that Gandhi's methods could only work because the British were liberal.  It would not have worked, they think, in Nazi Germany or Stalin's USSR.
Mahatma Gandhi's Rules For Social Activism:

1. Refrain from violence and hostility
2. Attempt to obtain your opponents trust by being truthful, being open about your intentions, using chivalry and making behaviour inoffensive without compromising the issue at hand.
3. Refrain from humiliating an opponent.
4. Make visible sacrifices for one's cause.  Here it is best if the suffering of the aggrieved is made visible.
5. Carry on constructive work.  Address parts of the problem you can address.  Make improvements where you can.  Participate in activities that all people see as contributing to everyone's common welfare.
6. Maintain contact with the opponent.  This is absolutely necessary if conversion is to succeed.
7. Demonstrate trust in the opponent.
8. Develop empathy, good will, and patience toward the opponent.  This the best you can do from your end.  If you fail to convert an opponent, it may be due to external factors beyond your control.

Gandhi's vision went beyond throwing the oppressors out by hook or  by crook.  He considered the oppressors part of the society and so long as they are not transformed into a new human being, the oppression would continue in some other garb.
For Gandhi the fight against the British was a radical experiment which would give rise to a new India and he wanted to use the new India to create a peaceful and just global society.  Who could be more courageous than Gandhi?  Satyagraha could never be conceived as the weapon of the weak.
Tagore equated Satyagraha to a thunderbolt.  He felt that "Passive Resistance is a force, which is not necessarily moral in itself; it can be used against truth as well as for it."  He was troubled by the negative impulses non-cooperation could generate.

To answer this question, let us look at satyagraha as conceived and practiced by Gandhi.  Satyagraha is a relentless search for truth; and is an effective substitute for violence.  Truth is the destination; satyagraha is the way, a nonviolent way.  Only those who are strong willed can tread on it.  It teaches us the art of living as well as dying for a cause gracefully yet without adding to the violence that already fills this world.
Satyagraha needs no outside help; it derives all its strength from within.  The method of Satyagraha required that the Satyagrahi should never lose hope.  Nor should he harbour ill will and enmity towards the opponent.  Satyagraha being a method of conversion and conviction, it prohibits the use of coercion.  Much depends on where and in what situation it is used.  Violence in any visible form is barred, no matter what the social context. Satyagraha not only involves direct action but also the education of the people involved in it as participants or recipients.
Two hundred years ago, the French philosopher Rousseau said: "The less government, the better off its citizenry." Adam Smith in his work 'The Wealth Of Nations' set forth three legitimate functions of any government: The judiciary; protection of the country against foreign enemies; and the infrastructure, such as highways, power, etc.  To these functions can be added the 'safety net'. 
This being the nature of the government, there is always need for movements to contain it and bring it on the right course.  People as individuals and groups would do the needful.  What satyagraha of Gandhi aimed at was to bring the government on the righteous path and at the same time train the people to be more righteous.  He wanted to change the course of the government and the people in the hope that a day will come when good people and good government would coincide.  Good people would emerge only if individuals feel themselves bound in a common bond of life; in the unity of the existence in the long run and that of humanity in the immediate run.  "People are related to each other in a way that is transcendental in nature and conflict should be seen as a gift providing a rich opportunity, potentially to the benefit of all, to realize a higher self.  A desired outcome of conflict, in this line of argument, is nothing short of the creation on a new social structure and a "higher level of self-purification in both actors."  Gandhi considered satyagraha as a means to change the nature of the government, and the satyagrahi as an embodiment of an ideal.

As time flows, generations of men and women come and go to merge in infinity, leaving behind a legacy of memories and traditions that shape the future.  Each generation has contributed to the making of the world we live in today.  The twists and turns in human history determine the content and shape of the world in making.
The world we live in today is a world of violence: violence against nature; violence against fellow human beings; and violence against oneself.
To bring peace in the conflict-torn world, we have to educate ourselves to be at peace with ourselves.  We must move forward from our animal ancestry, which Gandhi called brute force.  We must learn to respect the dignity of man and nature and find social and political solutions to conflicts so that they do not reach the flash point of violence.
The time has come to pause and think.  Should we continue to advance materially at the cost of our survival, use science and technology for our own annihilation, lead a life style that makes us sick?  Should we not use the growing pool of knowledge that we have accumulated to make this world a better place to live in?  These and many other questions aroused a response in Gandhi, which he called Truth and Nonviolence.  When translated into action, they together, gave rise to Satyagraha.
While violence and nonviolence are contradictory, they are marked with commonalities in many ways.  Both are conflict resolution vehicles; both need bravery, courage and will power.  Only the goals are different.  Violence aims at subduing or finishing the opponent by brute force; nonviolence aims at winning over the opponent without hurting him by soul force.  "I have said time and again that Satyagraha (nonviolent struggle) is not the same as making peace.  It is still a fight that has to be fought bravely as a soldier in war ―just the weapon is different."

Anasakti Darshan Vol. 3, No. 2, July-December 2007