The enemy was clear.
It was pretty much based on geography.
No such distinction exists now.
In other civil wars/civil disturbances, combatants tend to self-identify.
/johnny
Actually the two sides would be similar to CW I: it's city vs. country. Communists mostly grow up in very high population density, Americans mostly grow up in low population density. The suburbs are a mixed bag. Wipe out LA, Chicago, NYC, and the hostilities would effectively be over. Hack the food stamp system and the 'rats will burn their own nests to the ground.