But post this as a diary here. In the long run, we're all dead. John Maynard Keynes
Supporting the attempts by Brũning, Schleicher or Papen to run a "presidential" government (ruling by emergency decrees issued by Hindenburg)? Ironically, I think that in the power game around the monarchist Hindenburg, getting the support of the communists would be a kiss of death. And if one of those had won, I doubt Thälmann would have stayed free long anyway.
He went for the only option that could lead to power for the communist party, building organization and support until they could do a revolution. He failed, but not from not supporting the lesser evil in 1931. And the remainders of the organization worked as resistance within Germany. A vote for PES is a vote for EPP! A vote for EPP is a vote for PES! Support the coalition, vote EPP-PES in 2009!
The whole misfortune lies in the fact that the policy of the Central Committee of the German Communist Party, in part consciously and in part unconsciously, proceeds from the recognition of the inevitability of a fascist victory. In fact, in the appeal for the "Red United Front" published on November 29, 1931, the Central Committee of the Communist Party of Germany proceeds from the idea that it is impossible to defeat fascism without first defeating the Social Democracy. http://www.marxists.org/archive/trotsky/germany/1931/311208.htm
I don't want to get lost in the details of Weimar history. The point is that the far right in the US is a powerful political force with a clear willingness to use violence and with a large militia activity on its "fringes" and that it would be suicidal to underestimate its potential in the course of lashing out against the Obama government.