"Isn't Revolution Violent?"
"Those who make peaceful revolution impossible will make violent revolution inevitable."
- John F. Kennedy
"We will be non-violent to those who are non-violent to us."
- Malcolm X
Most people are afraid of or are disgusted by violence, which is a good thing. When socialists talk about revolution, people automatically associate revolution with blood flowing through the streets, mindless slaughter, indiscriminate killing, and so on.
These misconceptions about what a revolution really means are part and parcel of what we learn about revolutions in school and in our textbooks. They tell us about the "Reign of Terror" during the French Revolution, in which thousands were put to the guillotine by Robespierre and the Jacobins. What they don't tell us is that more people died in the areas occupied by the armies of the King and the other Kings of Europe who felt threatened by the revolutionary upheaval in France.
And, as Mark Twain put it, "One reign of terror lasted 1 year, the other lasted 1,000 years". You cannot say that the violence used to overthrow a monarchy and establish a (bourgeois) democracy is just as bad as the violence used by that monarch to keep the people down without being a hypocrite.
If the goal is to change the system fundamentally - if the working class is going to seize power from the capitalists - then some amount of violence will have to be involved, for two interconnected reasons.
The first reason is that the ruling class - the capitalists, the generals, the politicians, the chiefs of police - will not surrender their power unless they are forced to. Bill Gates isn't going to say "well, you guys out voted me in the workers' council, so I'll just step aside. Here are the keys to the factories and offices, and here is my PIN number." The ruling class can't even allow people to demonstrate peacefully without sending thousands of cops armed to the teeth, dressed in riot gear, much less allow the people they exploit to take their property and their power.
The second is that, as Karl Marx put it in the German Ideology: "revolution is necessary not only because the ruling class cannot be overthrown in any other way, but also because the class overthrowing it can only succeed in ridding itself of all the muck of ages and become fitted to found society anew." In order for the working class to become capable of running society, they are going to have to fight the capitalists for power. In the process of fighting, they will throw up organizations (workers' councils) and figure out how to run things without the bosses.
The capitalist system cannot survive without violence - without cops, courts, jails; without a standing army, tanks, and even nuclear weapons. The capitalist system inflicts violence on people every day, either through war and carpet bombing, or by starving people to death and denying them health care. Of course, our concept of what is and what isn't violent has been given to us by the capitalists: revolution, the majority taking up arms and taking over from the exploiting minority is violent; closing a hospital, warehousing people in prison, executing people, and spreading poverty are not violent, even though millions of people are maimed and killed this way.
The violence required by a revolution would only be a fraction of the amount of violence that the capitalists need to maintain their domination, both over workers and their commercial rivals. Think about it: does it take more violence for the majority to suppress the minority, or vice versa? In a real, genuine revolutionary situation, the army splits along class lines. The rank-and-file of the army are won over to the side of the workers and the oppressed (their brothers and sisters), and the generals stick with the capitalists. And once that happens, the amount of bloodshed is minimized.
When the revolution in Serbia overthrew Milosevic, the police and the army whistled and looked the other way; consequently, there was almost no violence at all. If Milosevic bunkered himself in a basement with anthrax and nuclear weapons, there would've been more violence. The amount of violence in a revolution is conditioned by the degree of resistance by the exploiters and their hangers-on.
To give up on revolution, on changing the system fundamentally, on the project of winning a world where ordinary people have control over their own lives because of some amount of violence will be necessary to wipe out the world's biggest parasites, murderers, and thugs is to ensure that they will rule forever, and that millions of people will suffer and die at their hands in the future.