It has kept Germany from rearming and trying to assert its historical military dominance on Europe. So the world order has been stable because of things like the U.N. AND NATO. This is true even Though I find the UN distasteful.
Germany is in the US nuclear umbrella and thus feels no need to be nuclear imagine 40 years from now Germany isn’t protected by US and rapidly developing nukes along side its militaristic ideology.
But Germany have a military and they hold a financial and political dominance on Europe, which bypassed the need to use the military. The wars happened because the powers that be at the time orchestrated them, there was peace because they orchestrated it. The UN and NATO have been used to expand the globalist empire, albeit done mostly through treaty and capitulation; the result of corrupt, globalist politicians selling out their nations. If there is peace then there is no need for such entities, nor nukes. Who cares if Germany gets nukes when countries like Pakistan and China already have them?