AHC: SPD Supports the Wilhelmshaven Mutiny

How could you get the cautious German SPD to throw in their support for the Wilhelmshaven Mutiny and broader revolution? What would be necessary to make this happen?
 
I suspect this may mean that their tenure in government would be relatively short. Neither the Freikorps or the Army would give their support to a revolutionary party, and the middle class voters who supported it in 1919 out of fear of the far left wouldn't either.
 
Top