The US is always under threat but we do not always know when. Our government does not tell us about every threat or people would act nuts and be in fear all the time. We hear when it looks bad or one of our allies are threatened too. But we don't hear about all the threats, and we should not. Not all of them are real or credible.
We've been under treat for quite awhile now by North Korea. They don't have much nuclear power though, so we should be alright. We could blow them to pieces. Lol. They're just a poor country that needs some publicity.
Yes. The biggest threat to the U.S. are liberals. They are destroying us from the inside. They are eroding at traditional American values. creating problems where they don't exist in the first place, and ultimately have an anti-American agenda. Abraham Lincoln even said in a quote that America is threatened not by outside threats, but when we falter on the inside. That is really what we need to prevent now before it's to late.