If I'm reading this right, I'd put the Republicans and Democrats at stage 6 hurtling towards stage 7.

And that puts them beyond any path to resolution but intercession, intermediation, arbitration, court action or forcible intervention

As there's really no one to do intercession, intermediation, arbitration or court action (at least not anyone perceived as a neutral party) we're staring at forcible intervention as a country.

One could argue that the SCOTUS was designed to do court action, but as they are already on one side that'd be out the window.