I think the idea of "communist threat" was so closely tied with "soviet invasion" that everybody forgot the communists rarely operate in the open. Of course the USSR would use covert and psychological tactics to defeat the US, they didn't stand a chance in an outright military conflict. The US did not defend against those tactics enough, possibly because they're too hard to fight against in a country like the US - fighting that battle requires a certain degree of curtailing civil liberties, which never would have stood, and consistent strategy, which given the change of government every 4 years is understandable.