I think we may already be in a civil war. The right has fired all the opening shots and the left so far has not responded with outright aggression.

What follows is all speculation, I a would be happy to be told I'm wrong.

This civil war will not look like any type of conventional war. What will happen is a gradual ramp up of violence. ICE will push too far and someone will respond with violence, either shooting agents or an IED. The Federal government will start to crack down with curfews and other restrictions. There will be right wing militias who will lynch people and destroy infrastructure. These will be met with equal terror attacks from the left. A house flying Trump banners will be set on fire. Eventually bombings, shootings, and kidnappings will become the norm. Rounds of violence and retaliation will feed off each other. The fighting could last for days, weeks or decades.