This isn't 2001. Fox News -- which ironically only became relevant at all because the Bush admin gave them exclusive access during the Iraq war -- has effectively destroyed America's unity in the two decades since.
And also to point out in the parent's comment - an external threat would have to -feel like a threat-. Attacking just NYC wouldn't do it for that 35% of America; it's not a threat to them, but to those 'Demoncrats'. Hell, the de facto leader of that 35% just asked the likeliest person to orchestrate such an attack to share dirt on his political opponents here.
The real threat to the USA is ourselves, not something like WW3.