An 84-year-old incumbent party-line centrist was running against Hitler, and the left party at the time spent all its time attacking the centrists (they called the establishment left party “the main enemy”), and ran their own third-party candidate in the election, siphoning votes away from the center.
A few years later, Hitler had managed to seize power and most of the leftists were in the camps or dead. They were the first of his targets, even before he started working for real against the Jews.
I’m being a little bit selective about it to emphasize the similarity with today, and glossing over some important differences in the situations. But also, the situations are eerily similar, at the core.