This is why we had The Cold War.
Japan attacked by surprise during a Peace Talk with our Secretary of State. We had the firepower to easily defeat the invader if we had even 10% of our men on Alert.
Lesson learned. We have kept men on Alert for decades as a result. Our current and future enemies will also strike without warning.
There was no one more surprised than the Japanese that the US forces were not on alert. A declaration of war was supposed to be delivered before the attack. It was a communications failure on both sides and a leadership failure on our part. When the country is in "peace" negotiations to avoid a war, it is the military's duty to be prepared if those negotiations fail. Ours wasn't, theirs was. As soon as a war is over, we as a country seem to say, "that's it, let's go shopping" and forget our military. We did it after WWI, WWII, Korea, Vietnam, the Cold war and we are doing it now. Fortunately, until the current administration, the military itself stayed alert.
I designed some really neat stunters while on alert duty and had the sh** scared out of me a few times when we actually launched the planes with armed weapons that were officially not there. I hope that it is still true today, but I fear it is not.
Ken