probabilites of USA invasion based on historical precedent

probabilities of USA invasion based on historical precedent

fiction
edward w pritchard

While our leaders debate the need for a wall from San Diego to El Paso to keep families from the Southern Hemisphere out could our real enemy be 30 million Chinese  and Russian troops in new warm parka's and boots tramping from Alaska to Florida over some perceived slight to their Country's sovereignty's?

What are the historical probabilities of USA invasion based on historical precedent. -As I recall the classic historical precedent would be the eventual fall of ancient Rome caused by the Rhine freezing December 31st 406 and a mixed horde of soldiers eventually taking a walk towards Rome.

I haven't heard anyone else thinking along these line. It must be unlikely.