Actually, I think "we" have known it. I believe that is part of, if not the entire reason for the deplyoment of our fleets, the moving around of resources and the cancellation of leave for many. I must state that that is only my opinion, but I'm fairly convinced there's a whole lot more saber rattling going on beyond our eyes and ears.
We live in treacherous times my friend.
I often compare it to the 1938-39 world scene. We know its coming, we just dont know when the shoe will drop.
I honestly believe there are many combinations of effort stemming from belligerent nations, terrorists, globalists, and outright socialist/communists designed to destabilize our domestic politics and create chaos/confusion within our country.
I often wonder if the hostiles are on the same chapter of anti-US playbook, and have combined to use their resources in one coordinated attack which would be designed to cause as much devestation and degradation of our capability as they possibly could.
Like one Jihadi said "eventually, China will come in our side and the US will be destroyed".
There is a time to come when we all will have to rise up and challenge these threats individually, just like our ancestors had to do.