> He considered Kautsky a most excellent Marxist until Kautsky supported
Germany in WWI
Wait a minute, this is not true! Whatever else one thinks of Kautsky, he did not join with the SPD parliamentary leadership in supporting the war!
He suggested the SPD delegation abstain from voting rather than vote for war credits. About a year into the war, he joined with Bernstein -- that great revisionist bogeyman -- in **denouncing** the pro-war SPD leadership!
Lenin's later break with Kautsky had to do with his attitude toward the Russian Revolution, not anything to do with WWI!
And remember, Lenin actually supported Kautsky *against* Rosa Luxemburg during the mass strike debate. I think Lenin and Kautsky were wrong in that case. However, I like to think Lenin tacitly admitted Rosa was correct by calling for all power to the soviets.
Nonetheless, I agree with Louis Proyect that any party-like project in the present era means constructing "Kautskyite" parties: large, multi-tendency socialist parties with reformist and revolutionary wings. That is basically what we are trying to create with Die Linke. Oskar Lafontaine even openly claims the legacy of the USPD.