No forgetting either empire, but the world has changed. Napolean's example, where the locals never ever accepted his rule and were always eager to throw it off when he was busy somewhere else seems to fit what we see happening in Iraq better. The modern world's nationalism has sort of made Empires difficult to keep.

The US is just not cut out for that path anyway. Neither the British nor Roman would ever have made the mistakes we made immediately after active combat in Iraq. And if the old Imperialists were there now, they'd be burning villages and slaughtering hostages as we speak to stamp out attacks on their troops. Neither of us expect that from the US, do we?