I dont think fusion ballots actually do anything other than like, promote that party on the ballot basically. It doesnt give it any sort of power or anything, the candidate is still a democrat. WFP does that and it doesnt mean anything, frankly dsa has more influence than them. But also political parties in the us dont exactly work the same as in other places. What exactly is the democratic party doing to "crush any attempt at being socialist" that wouldnt happen to a politician thats in another party? I dont see what would play out differently. I dont think that elected socialists are bound by some chain by the party. Either way the usefulness of electeds is to primarily push class struggle politics while running and when in office, not to actually bring about socialism through the state.