I’ve found both of those before, the second one quotes it as “Herr Holtermann proudly predicted” so that doesn’t work.
The first one based on Google Books is an unattributed chapter title, and searching doesn’t find any German words for slogan or motto in it. And Rudolf Olden is prominent enough that I think someone would have cited it by now if he had a KPD attribution in there.
“Find me someone who attributes it to the KPD in a contemporary document.”
[finds you a contemporary document]
“Well, he doesn’t academically cite his sources or literally call it a motto!”
Yeah, that’s about what I expected.
Relax I’m not fucking with you I’m actually interested in this. There are a lot of contemporary documents, there are a bunch of 1933 SPD newspapers with “Nach Hitler kommen wir!” on the front page, the problem is finding anything that isn’t quoting Holtermann.
Why did the Marxists fail is the closest I’ve found, because he doesn’t explicitly say who he’s quoting. You can read this anthology version of it which unfortunately edits out the actual quote, but Olden is very critical of the SPD for acting like there was an electoral or legal solution to Nazis instead of planning for a civil war, so I really think he’s quoting Holtermann.