In the op?
Isn't it "if many powerful people believe that they can use the population under their control to satisfy their megalomania"?
WWI should probably have been resolved by not stopping the murder at Archduke Ferdinand but continuing on to any Royal/controlling person who thought going to war was a good idea.
Do nations of people actually care if they're "#1"? People on the whole want local things AFAICT, sufficient freedoms to raise their family and achieve a degree of fulfillment in their lives.
Violence has a strong tendency to seem more like a good idea than it actually is.
It was pretty tongue-in-cheek, but I was saying from that point the Royals involved could have solved things without having a World war.
Edward and Wilhelm could probably just have been spanked by their nannies and sent to bed without any supper.
I'm not well versed on it but WWI always seems to me like a duel in which the factions chose 'millions of other lives' instead of swords or pistols.
1) The divide between nation/leader is not a valuable one to make in-so-far as whether it was originally their idea or not, the nations were the ones doing the warring. I think it's dangerous to think of history as caused by individuals (despite the tendency of the textbooks to tend that way). Could the world have been different if Hitler was a better person? Sure. It also could have been different if the people were better too...
2) I can think of many counterexamples to people wanting local things. You might argue that there is a way to fit things like America's current trade war with China into the deep South's degree of fulfillment, but I'm not really interested in going down that hole. I'd rather just say that, as stated, I don't think it's a predictive model of the world.
If Hitler was a better person, he probably wouldn't have gotten into the position he did, and we'd all be invoking some other German's name as the ultimate bad-guy. However, it's also possible that the NSDAP would have picked some other fool as their leader, and that person would have been less competent, and they would have been much less successful in their war campaign, or perhaps not even have gained the power they did.
But the ultimate reason Germany took the path they did is because of the way WWI turned out for them, and the horribly punitive measures they were forced to agree to by the English and French. The world would be very different now if the English and French hadn't been such assholes.