We have no weapons on board, Sir. But we can charge up the communication laser and cut their planet in pieces One of the reasons why we have such a developed brain is because from the dawn, man had to fight the deadliest beast on Earth another man. More brain is good . But we should not overdo it. Losses that humanity takes every day from war, are insignificant compared to loss of life in car accidents. But the war is one of major drivers of progress. In many cases violent solution is the only solution. From a perspective of a slave, towards his owner. Slave is breaking the law here. Sociological role, violence takes a role of pain. Pain allows the organism to understand that something is wrong. If the slaves are not revolting, humanitarian part of society has no reason to worry. They think all is OK, that the slaves are happy with their position. There is just not enough cookies on Earth for everyone. We need to fight to evolve, there is no real difference if you are fighting with guns and missiles, with banks and cash transfers, with ideological speeches and faith. (Personally I like giant human like robots most) .
Oil industry experts say oil will run out "sometime this century", so after that we'll have nothing to make our planes, warships and tanks go, and will be plunged back into caveman times, having to fight with sticks and stones, right General? "Ugh.."
The world got along fine without crude oil for thousands of year and were able to fight thousands of wars. Coal use to be the source of energy. Pig lard makes an excellent lubricant.