The Age of Empires
http://www.krysstal.com/democracy_whyusa01.html
I haven’t had time to verify these from another source, but it wouldn’t surprise me. I’d be interested to read an analysis of economics correlated with empires. For example, during the Age of Mercantilism England became the dominant impirial force, and I think that there exists a strong argument for calling the US the dominant impirial force during this age of Democratic Capitalism. It’d be interesting to see if you could look at all empires through history and define their reign in terms of the dominant political-economic system.