Blue, those wars were inevitable as all wars are for one reason alone:
Population pressure caused by a scarcity of resources.
Let's take WW2, for example. We, the Allies and the Treaty of Versailles, directly caused World War 2. We bankrupted Germany. So you had mass unemployment, mass hunger, a weak central government, uncontrolled inflation, and a loss of national pride. The only way to fix those things is go to war and start hoovering up resources as fast as possible. That keeps the mob from hanging you, the leader, and allows you to win political points by saying "See? We're fixing things!"
Literally every single war is about resources when boiled down to their purest form.
The Civil War? Lack of cheap, human labor that an entire agrarian industry was built upon. So much so that it was mentioned 23 times in the Articles of Secession. I'll leave the moral and ethical debates about slavery out of it.
The Second Sino-Japanese War? Rubber, oil, and iron.
The Iraq War? Oil. It was always about securing continued oil production from OPEC nations and we took the initiative to keep OPEC's hands clean.
So long as humans breed in an uncontrolled fashion, inefficiently produce goods, and value convenience over sustainability, there will always be war.
Or, as Ron Perlman likes to say:
War. War never changes.
"Lock the doors. Kill the light. No one's coming...home tonight. It's getting colder."
If you would like help or further details on a technical discussion we're having, email me at bnhelp (at sign) keepusiel.net .