It can only work at the local level. At the national level it's always been a waste of energy to do entryism, the party is too good at propping up corporate dems to primary effective leftists with AIPAC money. The ones who remain become Pelosis, such as AOC. It's a strategy with a bad track record, it seems like the easiest path toward power but it's not a coherent solution; activists work outside of the Demoocratic party then people like AOC suck the energy out of any movement and take credit. We can still use the Democratic Party as a springboard since most of the people who are already sympathetic to us are currently Democrats, flip the script on them, but to try to build the left inside the Democratic Party is just asking to be undermined by opportunists.