Complex sentence: Commentator Steve Sailer has argued that the theory of acting white is a red herring, and he has also argued that inate genetic differences in intelligence that vary between races cause racial differences in school success.
Split into simpler sentences: Commentator Steve Sailer has argued that the theory of acting white is a red herring. He has also argued that inate genetic differences in intelligence between races are the main cause of racial differences in school success.