

most of his supporters absolutely hate Hillary Clinton so they didn’t vote for her and then Trump won his first election.
6-12% of Sanders supporters voted Trump. ~82-83% of that 6-12% were conservatives. Bernie had broader appeal with everyone except the “vote blue no matter who” crowd because policies that immediately improve people’s material conditions are popular. Telling someone who is struggling to make ends meet “America is already great” is not popular.
For comparison, 15% of Clinton primary voters voted republican in 2008
Primary them, but also make it as clear as possible, before, during, and after the primary, that republican-lite is not electable because the DCCC has shown time and time again they will put as much weight as they can on primaries to make sure the left doesn’t win, from blackballing any companies and staffers that support a primary against an incumbent (this is never applied to primarying progressives or companies that help elect republicans) to defunding state party’s funds and quitting if the progressives take control of the state party.
If the left candidate doesn’t win, I am not voting for a republican-lite and giving them further power to the guys we see rolling over for fascism right now.
That is what the tea-party did, and it scared the republican party in line, and the ones who didn’t toe the line, but still managed to win primaries, lost general elections.