You mean the SPD that used the Freikorps to crush the communist Spartacus League? The Freikorps that went on to aid Hitler in his rise to power? The SPD who prevented a communist revolution that could have prevented the rise of fascism in the first place? That SPD?
“However, many Freikorps also largely despised the Republic and were involved in assassinations of its supporters, later aiding the Nazis in their rise to power.” https://en.m.wikipedia.org/wiki/Freikorps
Voting hasn’t had a good record at stopping fascism fyi