I'm meaning blue water navy in terms of the logistics involved in invading and then supplying that invasion force. It seems as if you think China (already) has a blue water capable navy that could send troops to the US and then provide them with the long term support they would need to be successful(reinforcements,food,fuel,ammunition ect.)... China is
working towards developing a blue water navy but as of 2022 they can only operate in a limited area around China
https://en.wikipedia.org/wiki/People's_Liberation_Army_Navy so if they did launch any type nuclear devices then we would be in a nuclear war not an invasion type confrontation where troops and their logistics followed like in ww2.
No, I don't think either China or Russia is planning on doing that. Completely unnecessary. Imagine NY, Boston, Washington DC, Miami, Houston, San Diego, Los Angeles, San Francisco, Seattle, Chicago, Philadelphia and Baltimore are all wiped out -- suitcase nukes took out ten square blocks of the downtown area and spread a cloud of radioactive dust over much of the city. All electricity is down, all trucks are down, police are in chaos, there is widespread looting, rioting and panic. But it is worse than that. The entire coastline was hit with a tsunami that went in over a mile with radioactive water washing out bridges, damaging roads, etc. Millions of refugees flee inland while over a hundred million people are killed in the initial attack. Our ports, our imports and exports, Wall street, banking industry, insurance industry, they are all completely bankrupt. The US dollar is worthless.
Now I doubt the US doesn't retaliate. So Russia and China suffer significant losses themselves. This includes the 3 Gorges dam being blown up wiping out roads, bridges and the industrial heartland of China where 500 million people live. I would think Beijing and Moscow would also be hit. As a result the world's economy is also a total collapse.
The perfect setting for the Antichrist to ride in on a white horse, get people to hand over their freedom in exchange for order. Then you send in UN peacekeepers to places like the US heartland, basically Chinese and Russian soldiers with blue helmets.