Vote for the change you want to see.
The Republican party got remade because trumpists showed up and outvoted the party elites. No reason it can’t happen for the Left except for laziness and apathy.
If all the progressives furious about the state of affairs now had shown up for Sanders in 2016, I doubt we’d be in this hellish timeline. Sadly, he needed the young progressive vote to show up.
Party Control of Party Primaries: Party Influence in Nominations for the US Senate
That’s not being rigged, it’s a Democratic Party election. No shit someone from outside the party will have less influence.
Unfortunately I cannot read that paper without paying money to a journal. Would you care to provide a summary of the methodology?