We can debate the finer points of social democracy and democratic socialism once we’ve defeated the reactionary right and neoliberal center.
Define them correctly, and fight for the right thing rightly defined. Otherwise, you'll find even more people in office you'll later be regretting you backed. There have always been turncoats who really always intend to do just that, but let's work on minimizing, and even eliminating, them by proper screening and via legislation (planks in the hard and fast platform) forcing office holders to stick with the planks or get permission from the Party to change or be instantly ousted.
Better yet, start the Progressive Party already. It would be fine with me if it were named the Democratic-Socialist Party just so long as that's what it really is: democratic-public ownership of ultimately everything, totally bottom-up.
There's plenty more to say on the whole subject, but this is good enough for right now.