both Post and Muldoon focus on Kautsky’s post-1910 period in which his politics were, yes, increasingly reformist — but also less and less influential.

Despite his steady turn to the center after 1909, Kautsky’s entreaties were ignored by the bureaucratized officialdom of the German Social Democratic Party (SPD) throughout the revolution. Germany’s radicals, on the other hand, rejected their former mentor for having abandoned his long-standing commitment to revolutionary class politics.

Up until the early 1910s, Kautsky was the leading light of the far left in Germany, Russia, and across the world. It’s hardly the case that Kautsky’s writings were to blame for the German social democracy’s slide to the right.

Jacobin columnists trying to explain how Kautsky and the SPD sliding to the right at the exact same time had no connection.

Could this theorist and prominent figure within SPD have some input in their shift further and further towards capitalism? No it was the shady unnamed bureaucrats.