Could another country invade the USA? what if they just focused on Washington DC?
I got to thinking what if China just focused on invading all the main buildings (including the White House and the Pentagon) in Washington DC and started taking everyone there hostage. All the major politicians and higher ups... possibly including the President and his family.
You don't so much worry about any other major cities... just Washington DC.
You start with a few EMPs, send out a major computer virus, and then you take over Washington DC... that would be my strategy.
If America retaliates with a nuke they lose everyone in Washington DC.
obviously there would need to be motive for such an aggressive invasion (9/11 being an inside job perhaps), and the UN would have to support it if not before the strike but soon after(months).
and Russia would have to be China's ally on this. China could just send North Korea's troops to do job... and once they all get killed they send their own, and then Russian troops.
Oh and I'm sure Venezuela and Cuba would love to join in the action by sending a few of there own troops to keep America Occupied.