If it cannot be attributed to Hackers then likely Russia or China is behind ATT shutdown nationwide

There have been many threats to do exactly something like this especially by Russia lately. We have been hearing these threats almost weekly or daily by the way. So, logically then it likely is Russia doing this to ATT if other hackers not a part of a government can't be found that are doing this.

Since doing this by a government like Russia would be an act of war it is sort of like when Kennedy was assassinated we didn't blame (the government didn't blame) Russia or Khruschev or Castro because it would have led to a nuclear war at that time. 

Likewise now, it is likely Russia Again doing this to see what the U.S. will actually do in response to such an "Act of War" by Russia against the U.S.

So, watching how our government deals with this possible "Act of War" Against the U.S. might be interesting, especially if it came from a country, for example, like North Korea or Russia.