Look amigo, how can millions of troops and materiel get transferred from one country to the next without being detected? Even if you could accept the absurd premise about the entire U.S. intelligence system being disrupted, there’s just no way a huge movement of military might could be transported without being noticed by larges amounts of people. I realize movies are exercises in suspension of disbelief, but the “Red Dawn” flicks strain that that belief to the outer limits and beyond.
In the first Red Dawn which was set in the 80s. It might have been possible. If the attackers had intimate knowledge of our sat system and was able to mask movements using holes in coverage and such. But it would have taken a huge effort and slowed down their advance to months I remember talk in that movie of slipping up through Mexico and down through Canada and using private airliners and such. But still it would have been near impossible to pull off a total surprise attack.
Today it is totally out of the question. You might sneak a couple hundred troops in at one time but a full fledged battle force won't get within 500 miles of our borders without us knowing about. Hell we will know when the start loading their troops into ships and/or planes at their own military bases. And I am fairly sure our battle doctrine will be to engage these units long before the get near our borders.
It's not a question of detection. It's a question of initiating a war over that detection, something the US rarely does. We go to war AFTER being attacked.
You think the US would invade Iran to stop their nuke program?