There have been many, many wars in the history of humankind. As a matter of fact I don't think that there has been a single day on our planet ( at least in the last few hundreds of years ) without someone fighting and killing each other in a war. Interestingly lately there have been more and more wars being led in the "name of peace". There are different names for it ( e.g. "war on terror" ) but in general the idea behind it is to establish peace.
Now... the question is if it is possible to establish peace with war ?
The answer to this question is clear - at least to me. War is the opposite polarity of peace and it is impossible to establish peace with war. If that was effective, we would not have any wars on Earth long time ago. But this is not the case. The reason for it is that with war, we can - through fear of punishing or killing - force others to behave in a way which is being regarded as peaceful. But we miss one important point - this peace will last only as long as the position of domination together with this fear of being punished and killed is being continuously maintained by the peace-maker. And we can see it all over the history of mankind. As soon as the position of the domination of the peace-maker is being weakened, we have almost immediately war as a revenge etc. And sometimes it takes many years or even decades but eventually we have a war again.
The reason for it is that forcing somebody to behave in peaceful way is not correcting the source and the root of the war. The war exists in the minds of human beings, which together with fear of survival and egoistic tendencies manifests itself as a war in the outside world. Thus to stop all the wars, everybody must realize that we are one big family living on one planet and we must work and live together according to principle of what is best for all. Nobody is better then others. Nobody deserves more then others. We are all equal. If we share what we have, we will have more then enough for everybody and we will live in abundance. If we will insist on accumulating as much as possible for ourselves while others suffer because of it, we will have wars. It is simple but yet difficult to comprehend it by too many.
P.S. The only possible way that war will help to establish peace is when the shock caused by extreme suffering will make people to wake up, open their eyes and say: "WTF am I doing ?". And if in this moment there is enough people who realize that war will never bring the peace and they start to work together ( the oppressors and the victims ), then there is a chance that we will have peace. But why do we want to suffer instead of realizing it now without war and direct this point in peace ?