War is not necessarily carrying guns and missiles ,these days wars are been fought with wisdom not with bombs and riffles, there something we call economic war ,Ban and sanction like we experience all nations against russia not necessarily done violently but with wisdom to affect it economy ,once money is not in circulation again it will lead to protest by his people against his government for dissatisfaction.
There is also another way which is something called Bio war. 
It maybe the part of human evolution, we used to fight with bow and arrow then knife and then guns and tanks now the next stage of the evolution but the main intention is crush the economy of opposition and take over the control for that people can go to any extreme.