The insoluble problem is that wars happen when leaders want what somebody else won't give them, or they need to punish other leaders for trying to grab something of theirs. Or they want to forestall a rival from striking first. Or they want revenge.

And much of the time the led are all for it.

No need to invoke genes, testosterone, -isms, or anything else. Kids will steal unless they're taught not to.

Unfortunately, leaders don't have parents to discipline them.

The pacifist movement and the League of Nations couldn't do it, and the UN hasn't been able to do it.

Even the threat of nuclear weapons has been less than entirely successful. Both the US and USSR were nuclear when North Korea invaded the South.

Everybody able to make an atom bomb wants one, and everybody wants cyberweapons.

It's to get what they want, material or psychological.