how many ancient empires would it take to defeat Modern day USA?

Ancient empires are suddenly transported to our modern-day world and they all decide to work together to defeat America

R1 the entire US military no nukes are allowed the empires are bound to what technology they had at the time

R2 nukes are allowed but the empires are permitted to research and use whatever technology they plunder from battle

R3 WW2 era Germany is now present and wants to help the empires

edit: you all missed the point the us military would not be able to beat a thousand roman empires