Noble as these words are, I have to take some issue with it.
Generally speaking, they are true. Generally speaking they are logical. Generally speaking, if everyone adhered to them the world would become a better place. And generally speaking, I greatly admire people like Ghandi who actively took non-violence as their stance and not out of cowardice, but out of their faith in its ethical superiority. Truly I do.
Nevertheless, in the specifics, it has been my observation and also personal life experience that evil, power-hungry bastards will ride roughshod over such fine sentiments until such time as a force as brutal as themselves smashes itself unforgivingly into their frontal lobes.
I think that a truer, more accurate quote would be:
All that is required for Evil to triumph is that Good men do nothing.
– Anonymous*
I could provide many examples, hypothetical, historical or even personal. I will not provide the personal ones for obvious reasons, since they may have some legal implications for certain Good men (whom may have had to take action against Bad men) though in a sense they would really be the best examples because they would bring home the reality of it to at least those readers who know me and perhaps to others too.
No matter, we can take real life examples which if you care to, you can research for yourself (in which case may I suggest you buy and read the very excellent book, McMafia – Seriously Organised Crime by Misha Glenny, which is replete with them). Take the example of a Bulgarian modern slave trader, Tsvetomir Belchev, who actively kidnaps a bunch of 19 year old girls and beats, rapes and brutalises them into sexual slavery for his own profit whilst keeping them imprisoned.
What are we to do with such an individual? Are we to ask politely he become ethical? Are we to spend hundreds of thousands of dollars investigating him and his ilk whilst making sure we don't by golly-gosh infringe his civil rights while we do it in the scant hope to bring him to "justice"? What is justice for such a beast? A few years in prison? The rest of his life in prison working at hard labour in such a way that he becomes productive instead of consuming taxpayer monies in continuing to exist? How would you enforce such forced labour other than by force?
And frankly, would it not be cheaper to shoot him in the back of the head with a cheap bullet like the Chinese government does?** And indeed send the bill for the bullet to his family, though on this note, personally, I would certainly fund the expense of the bullet. Hell, I'd be quite happy to pull the trigger too if they let me. What about you neighbour?
How much evil, how much ruination must one human bring to the world before you say…well…ok…I take up arms.
I respect the Ghandis of this world. Truly I do. I look at them as some kind of strange, Quixotic creature from a world of myth. Even aware of their human failings perhaps in other areas, I do remain in a kind of mixed morbid curiosity and fascination with them. More so because of their human failings in truth. For it proves they are mere mortals and yet are able apparently, amazingly, fascinatingly, to do this fantastic, other-worldly thing. That I know with utter certainty I cannot. Will not. But ultimately, in the extreme, when all is said and done, truly, just cannot do. My heart, my soul, it is just not that way shaped.
What about yours? It is fine to wax philosophical, but what if you have a loved one brutalised by such beings as Belchev? What then? One rule for you and another for the rest of the world? Or could you seriously react with non-violence to such a creature as that? I seriously would like to know.
* Though often attributed to Edmund Burke, it is not factual that he is known to have been the originator of this quote.
** And even this, especially if you believe in karma or reincarnation, hardly seems like justice. Especially if you truly wish to help him evolve his soul quickly by paying back the whole karmic debt before he reincarnates the next time, thus hopefully ensuring he doesn't come back as just a slightly milder form of his current self. In such case, at the very least he should be beaten to death over a period of many days. One could possibly skip the repeated raping because to inflict that without having to resort to people as damaged as he is would be seemingly impossible. One could say the same of beating him to death, but I presume that if left alone in a room with say 20 or so of the strongest, fittest male relatives of the girls, armed with steel poles, I think the problem would be that his death and karmic payback would once again happen too quickly and thus not to sufficient exculpatory levels. It could also be argued that the gruesome event could actually be somewhat therapeutic for some of the executors if they are relatives of the girls. Don't you go believing that a good solid revenge does not appease internal demons. The reality is it actually does, and I believe some studies in psychology were even done on this by proponents of the argument against the death penalty and to their surprise it was found that revenge did have a positive outcome for the victims. Predictably the proponents then dismissed this by saying the positives of it did not outweigh the social negatives on society as a whole of having the death penalty. (I do not have references at hand, but if I ever bother to look for them I will update this post.)
A Martian in London 
Very thought provoking. I've a two-part answer. Firstly in relation to the Belchev case you describe – I only know of him what you have written here, but infer from your mention of profit that he wasn't the only person raping these girls, that there were other men involved in paying him for that 'experience'. If this is the case, then it is these men that need to be pursued as much as Belchev. He is a conduit for a wider population to participate in the degredation of another human being. If only he is punished (by whatever means) then another Belchev will pop up elsewhere and those others will take advantage of the 'services'. Remove the market and there ceases to be a need for Belchevs – naively simplistic, but there you go.
How would I react? It's hard to say. If I think about it too long then I start remembering what I've heard about the death penalty not being a deterrant, that having legalised torture in a society de-civilises it (if that's a phrase). I've answered a similar question on your blog before which I could go and look for so I can be consistent but I won't. Going on how I'm feeling at the moment I would opt for the death penalty on the basis that if it was a near and dear person to me who was abused and I couldn't live with the anger that I'd have for the rest of my life imagining someone like Belchev having a laugh and a joke in prison. I would want his life to end and for him to have no chance of experiencing any joy whatsoever again.
Thanks for your reply. I think the first part of it though goes into territory that really goes quite far beyond the scope of my original investigation. Of course Belchev was just the kingpin in a whole layer within layers of evil, vile perverts that as far as I'm concerned all merit the same end in Hell I would reserve for him if it were up to me. My original query though related really only to Martin Luther King's original quote and sentiment, and primarily from a personal perspective.