FDR is especially relevant to this topic.
The SCOTUS back in the day routinely struck down his New Deal, declaring it unconstitutional. So in response FDR calmly took his cigar out of his mouth, snuffed it out, unzipped his pants, and slapped his ABSOLUTELY PENDULOUS BRASS BALLS on the table in front of them and declared 'Either you pass the New Deal, or I'll keep expanding the Supreme Court until it eventually does pass.'
The SCOTUS, frightened both at the prospect of losing their individual power and of FDR's prodigious manhood, passed the New Deal. So yeah, FDR having a spine and playing hardball is what got us the thing that (amongst other things) A) pulled us out of the Great Depression, B) ushered in the Golden Age of Economic Prosperity, and C) has been a boon for underprivileged or elderly folk up to today.
FDR then went on to win so many elections it took literally Death himself to stop, and he scared the Republicans so bad they invented term limits just to prevent another FDR.
So not only will the future not look kindly on the spinelessness of today's Dems, history is also looking at them in disappointment.