The other scary thing is how the Roman Empire ended... IIUC (and that's a capital I, btw), a group of Visigoths penetrated the capital, killed a bunch of powerful rulers and left... the rest of the country couldn't handle itself and it led to the Dark Ages for centuries... The scary thing is how close the events of 9/11/2001 are to those very circumstances...

...Although a part of me fantasizes about the freedom which existed in Dark Ages....