What is Justice?

Justice is hard to define and it is even harder to define how justice should be achieved some say that it is right to kill in order to do just, some say the best thing to do to help the people that need help as well as to educate them so that differences and hate can be overcome. Now others again say that violence in limits is the key to justice and many drift between the two extremes on the one side war supporters who say 'If you are not with us you are against us!' and on the other extreme are the people that say 'Please all of you stop this senseless fighting and lets talk.'
Now the problem is a) indecision about these two points which of the two is 'better' b) media and politicians often paint war as something that it is not, as the purposeful fight for the good of humankind. War is not just in principal all involved sides usually break the rules of reason most soldiers if they survive continue to suffer under what they have seen and done for the rest of their lives. Now is it necessary to spend so many resources on wars that can not be won?
"War on Terrorism" is in its core principal wrong, you can not siege war on a concept or an idea, you might as well declare 'War on Dreams' because that is to what it boils down. If you finally kill all Al-Quaeda members what then? Does anyone honestly believe that the struggle will end there? The truth that the Al-Quaeda fight for an idea, a dream this is something can't shoot, bomb or eradicate it eventually comes back to the surface, violence at this scale does not help on the long run. It is true someone that kills innoncent people, POW and others that are so called non-combatants should be punished but that counts for the soldiers as for the so called terrorist, since you have to realize that those 'terrorists' do not fight without reason because they are fighting for freedom of something. Their methods only differ in one way from the ones western powers, eastern and all other powers use which is the sophistication of their tools.
So what makes us 'better' than them? The modern war has killed more than terrorism ever did, and remember just or unjust cause is only a question of perspective.