As I said in another comment, this mode of thought is completely defeatist. If you rule out the possibility of a violent uprising and look at how to change our system from within the system itself, the ONLY way to push the country left is for a dedicated bloc of people to refuse to vote for centrist Democrats for multiple elections in a row until the party center aligns with that bloc. That’s the reason why every one of the last few elections has been “the most important election in history” and all the other crap.