I want to know the answer to the following question:
What atrocity motivated a self-serving USSR to object to the provision of political killings drafted into the Convention?
All the background I'm provided with is that "The exclusion of political groups was in fact originally promoted by a non-governmental organization, the World Jewish Congress, and it corresponded to Raphael Lemkin’s vision of the nature of the crime of genocide.”". Is that enough to answer the question?