I think we are at step six.
The war is now already in process in Chicago and Portland. Governors and mayors have in effect declared these cities to no longer be American.
While you isolate those who want to burn it all down, who have nothing constructive to offer. Then you back away from the danger.
I might could argue we're at 6.5 as we've seen more militias form especially since the 90s.
Everything hinges on Trump. What a burden he is carrying.
I believe we are well into "step six" (Normalization of political violence) and sliding into "step 7" (Rise of militias and parallel forces)
The "Right-Wing" militias are completely infiltrated by government agents and are mostly suitable only for theatrical displays. They won't start anything of consequence, unless the government tells them to do something. They do have people who are skilled with some rather nice toys.
The "Left-Wing" militias have been leaching off of taxpayer funds disbursed by a network of NGOs for several years now. They are unskilled and poorly trained, but they were organized by full-time cadres who did have some training and skills. They have actually been deployed on armed attacks of Federal agents. So far, they have not been very successful. They seem to have a lot of grifters.
The good news is that the government under the Trump administration is moving to disassemble the funding sources for ANTIFA and its' associated franchises.
Muslim militias have been around for literally decades. They haven't done much yet, but they are active in cities with large Muslim populations.
Mexican Cartel militias are the real nightmare deal. They have been active for decades, they have skilled, trained people with plenty of operational project experience, and they have plenty of money for expensive weapons. Assassinations of political opposition and government officials are an annual occurrence in Mexico.
"Step 7" could become fully manifested very quickly. I do not believe there is a "big hurdle" to this.
"Step 8" (Trigger event) is really "living in a powder keg and giving off sparks". "Step 8" and "Step 7" might actually occur in reverse order.