I think it will go nuclear as part of the process to take the war to the continental USA.

Also, low yield high altitude nukes will be used to create EMP events.

Also not mentioned is that the economic part of this war will do huge damage to the US economy.

It is possible that the USA will be very quickly rendered a country that will be unable to participate in military war, especially far from our borders. When that happens, best of luck to you all in the rest of the world.

I suspect Russia and China will be major players, but the most irresponsible and destructive attacks will come from lesser and third world countries, particularly those with nukes and WMD's.

Expect every theater to light up, mideast, asia, Africa, South America, etc.