He was probably more responsible for developing the ideas and concepts behind the Nazi racial policies, as seen by the anti-Semitic views expressed in Mein Kampf and also the manifesto of the Nazi Party. However, in regards to the implementation, Hitler and the upper echelon might have ordered them but it was predominantly the divisions of the SS that helped carry out these racist policies on Jews and other non-Aryan races (eg - concentration camps, torture, Kristalnacht etc)