Wait a minute.
The original question was if the network outside the US was cut off would the blockchain inside the US be forked.

And all the posts have been of the opinion that as long as someone has a 300 baud modem connection to the outside world everything would be fine.

If the government was able to cut off only 80% of bandwidth from outside that means the miners in the US would be mostly communicating to the network within the US. They would be getting blockchain information mostly among themselves. Wouldn't that fork the blockchain?

Isn't that what a 51% attack is all about?

Does this make any sense?