Lighter Skin = Better?

[Anomalocaris]

Romans had guns?

History book. Read. Learn. Fucking try it. Y'know, just for a change.

Roman Artillery

And tell me, oh great American patriot, how many wars has the USA won without help from other countries? In your own time, like.

Don't be too self important. Just because British natives were still putting lime in their hair when the Romans came ashore didn't mean the Romans didn't subjugate plenty of other more advanced people with first class military technology, like artillery, equal to or better than Rome's own. Examples includes first the city states of Magna Grecia (archimedes and defense of syracuse ring a bell?) then Carthage, Macedon, Phrygia, Thrace, Pontus, Ptolemaic Egypt, and Seleucid empire of the middle east.

In the end, it wasn't the path Rome took that made her a really great empire. It was the fact she succeeded in clearing out all the peer power who could threaten her core, and kept that condition for 450 years.

As to the US, the only thing close to a peer power the US defeated essentially on our own, and was clearly capable of subjugating even if it could be said that we didn't, was Japan. Granted, if it were just the US against a continent dominated by Germany, unaided by Russia or Britain, it is not clear to me if the US could really achieve any decisive victory before the atomic bomb reset the conditions of warfare.

But however the US got here, all the peer power than could threaten American core was cleared out, which is something Britain never did. Also, except population and land area, the US remains globally more preeminent and influential than Britian ever was.