“What is the finish line these people seek to cross?”
A one-party system is what they seek. The elimination of conservatives as a political voice.
This is what was meant by "Fundamentally transforming America." They thought they won the revolution by republican means. When its consummation was denied them by the same republican means, they have gone militant revolutionary.
Which is as all good bolsheviks do. And until Trump came along, the GOP was willingly playing the role of Mensheviks.
Just like what they’ve done effectively in California. When you change laws when you are in power as a party. So as it basically results in 2 Democrats running against each other. You’ve effectively eliminated the power the opposition party and voice.