US Empire.......Definitely Not Infinite

Your forgetting the vast army of mercenaries the US now employs, like Kellogg-Brown and Root (KBR) and Blackwater.

I imagine the Roman Empire also made extensive use of mercenary armies and local population guard units.

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“The war is not meant to be won, it is meant to be continuous, the essential act of warfare is the destruction of the produce of human labour”

Definitely, especially towards the end of the Roman Empire, when native-born Roman birth rates were falling precipitously.

However, the mercenaries at this point seem to be mostly American mercenaries..............recycled marines, et al. Good for the private comapnies, as Uncle Sam provided the training, courtesy of the taxpayer.......(seems to be a lot of that goin' 'round).

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"When you change the way you look at things, the things you look at change."
-Max Planck