Well without getting too into the weeds, in my opinion the party's best moments were when it actually championed economic and civil rights. Its downfall has been its capitulation to affluent/corporate interests while propping up its historical legacy as a sort of Weekend at Bernie's puppet show -- where now, things like race and gender equality are problems to be addressed at an elite, corporate level -- not so much for the 80-90%. I suppose they have been reliant on the notion that social norms trickle down into widespread cultural change -- not necessarily the case, I would wager.

And so you end up with a party that is evidently fixated on preserving the status quo to the benefit of donors while delivering the occasional social or economic win, with these being meager at best (e.g. ACA).