No.
Rome fell (among many reasons) due to overextension beyond their ability to maintain and concentrate sufficient forces, alongside military invasion by multiple groups over many years.
Germany was going to fall in one of two ways, either economic collapse from a grossly unaffordable military buildup that was on track to bankrupt them, or getting into wars with powerful countries in order to help pay for said military buildup. They went with option B.
The US has no issues concentrating and deploying sufficient military force to defend itself, and isn't spending anywhere near enough on defense to make it unaffordable, spending about 13% of our budget on defense. (compared to over 100% [edit: of annual income, I mixed my figures inappropriately here] for the Germans) Most of our deficit comes from domestic expenses like health care.