My hope is that when Biden loses it will cause Democrats to do a Republican style autopsy of the party. Then, given her comments about sharing the same party as Biden, AOC and other progressives will form a new party in the same vein of the Republican Party being made in 1854. Many support Sanders' agenda. With enough momentum they could establish a new party and replace the Democrats.
The 2012 Republican autopsy said nothing about reversing half their positions and nominating the former multi-time bankrupt host of The Celebrity Apprentice then slavishly worshiping him as "sensible" types like Bill Kristol, David Brooks, Jennifer Rubin and others lose their goddamn minds even more than those making temporarily alliance with Trump.
What do you know about the foundation of the Republican Party and how it became the dominant political party for two generations? The coalition of Whigs, Know-Nothings, Free Soilers and anti-slavery Democrats that temporarily aligned during The War didn't come from a previous party coalition collapsing. The Whigs were a temporarily alliance opposed to Jackson, after he left the scene they slowly imploded and never truly aligned on any issues.
The Republican Party itself split in half within a few years of The War ending mostly over tensions the War papered over and then four years later the Democrats had returned as a nationally viable party. THEN to maintain the White House the Republicans agreed to abandon the South to the Democrats.
You can do a third party system in the country, it'd just be regionally based, ala Canada's. Blue states could have the Democrats vs. Socialists. Darker red states could have Republicans vs. Nationalists. And swing states could maintain Republicans vs. Democrats. But this raises my point above about the foundation of the Republicans, it makes a nice clean philosophical split between the parties. But parties don't split like this, not even in PR systems. They split over other reasons from the petty to the single issue to sometimes ideological. And then they still have to form coalitions in the end, as these parties would. If either of the current major parties splits in half for entirely ideological reasons, the other party becomes a big tent party that absorbs the lesser remnant adopting many of its issues.
I can predict that with confidence because it's what the Republicans and Democrats have been doing since 1854 as issues rise and fall and coalitions realign. Republicans went from the imperialist party to the non-interventionist to isolationist to JUST FIGHT IT HARDER to "no world police" to War Always Forever Everywhere. And this is just one issue. And many of the people were the same people. We can do it with all kinds of issues.
The foundation of the Republicans was different and a major impact because it did what the other parties didn't do, ran perpendicular to the dominant issue of the time and coalesced around that. The Democrats and Whigs/Americans settled their internal differences over slavery by an endless set of compromises that tried to avoid changing the status quo. The Republicans, no matter what else was in the platform (lots of warmed over Whiggism) aligned on a fundamental principle that slavery would be driven out of the country either immediately (the radical minority view) or over time (the vast majority view) if slavery could be halted from spreading into the territories and therefore future states. The Party itself fought endlessly over whether or not blacks were equals and preferred to discuss that after slavery was dying. (For those wondering they decided that they didn't really care if it meant maintaining political power.)
