The fall of empires is inevitable because they all follow the same cycle. Innate intelligence and fortitude builds the empire. More of the same maintains it.
Complacency sets in and people become smug, self-indulgent and lazy. Too lazy to keep the imperial forces up to strength and too lazy to even reproduce themselves. Client populations flood into the empire's base, reproduce like crazy, and by sheer force of numbers displace the imperialists.
Rome did not have a democracy, so its clients had to resort to violence to subdue Rome, which they successfully did. The newcomers did not build another empire of their own. They just fed off the remains of the old order until there were just people and nothing else of value.
You forgot they also caused the fall of the Third Reich, Mussolini, The Japanese Empire, the British Monarchs (as opposed to today's pets), the Tsar, the Kaiser, the French Monarchy, and set America free from England. While Conservatives have fought for slavery, monarchy, and chattel slavery. They also are the ones who ended the Roman Republic in favor Empire, you deuce.
The funny thing is an alleged "small government" flack, just argued that the British Empire was good.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.