Nine nations hold thirteen thousand nuclear weapons around the world. Had Ukraine kept the nuclear weapons it had after the break-up of the Soviet Union, this could be and most likely would have caused a catastrophic situation.
World peace needs strong leaders; economically, we can, as part of the nations of the world, exclude 100 percent of a government that decided to invade another country; a combined effort worldwide would spell defeat for any nation. This also means that we need to abide by the rule ourselves.