Well some of you guys must remember how to build simple things like spark gap radios, and if all you need to send is morse code it's pretty easy to set up a transmitter and receiver.
I'll answer this one first as well as address Streak's note that electronics will be defunct, especially without power. Since we have 3 years to "prepare", I would like to acquire a ham radio which, although "archaic",
SHOULD still work if electronic communications are cut. Solar panels/wind power and a generator/battery bank will be necessary. The Morse code generator
MIGHT work for shorter term communications IF you know Morse code...
We have a "1000-in-1" project kit from Radio Shack that should work.
This would be worst case scenario--existing communication networks will be a valuable asset and will either have to be controlled or destroyed depending on which side has them. (ie: cell towers, radio communications, OTA television networks, etc.) As they are propagandists, without communications the other side will be at a severe disadvantage...
Our actions should speak louder than their words, both then and NOW! PS: I wouldn't discount the value of CB radios, either but would be concerned with jamming or eavesdropping by the other side.
Any war will likely play along party lines sorry to say. I'm a Libertarian but would probably side with Republicans. So that puts most of us OUTSIDE large cities. It would be essential to keep the enemy INSIDE the cities where most of the major carnage will ensue. I'm talking piles of dead bodies because of rioting and food shortages. And no where to bury them so disease will be a killer also. They will inflict the heaviest casualties among themselves.
Once the "government to hand, then hand to mouth/pocket" stops, the SWHTF!
Preparation for an "emergency" should be high on everyone's list RIGHT NOW! Once supplies start running low, there should be an organized band of brothers that will pick targets of opportunity particularly those of whom may have had a large hand in creating the mess we would be in. I think a valuable target will be the slip-n-fall and trial lawyers you see on TV and hear on the radio. Liberal/progressive politicians will also be high on the list. Their may be necessary culling of useless people with no skills other than whining, complaining and protesting and sucking off Uncle Sam's teet. This will be the harsh reality of war and prisoners will only be kept alive if they can perform a useful service--there will be no time to teach skills or common sense...
Regarding our neighbors to the north and south, I think Canada will stay out of it for the most part but there will be volunteers that will cross the border on either side. There may be a swarm of Mexicans in either direction--I'd have to research to give a more enlightened answer. Not mentioned is that there may be other countries that will invade the US in our moment of weakness.
Before the FBI comes knocking on my door I need you to know that this is just a fantastical representative scenario we have concocted and I hope for my kids' sake it never comes to pass. But my kids have heard my anti-indoctrination and know many valuable hands-on skills, so I hope they will be survivors in the event of an apocalypse. More likely IMO, is a natural disaster of a scale never seen before or maybe even a HEMP over the western coast courtesy of NK.