Why was Bush Sr. National Security Council so effective, and Bush Jr National Security Council so ineffective?

I figured that given Condoleeza Rice being Brent Scrowcrofts protege, and given Bush's Srs relatively well handled foreign policy affairs(hopefully ping those attributes to his son), that Bush Jr and his NCS would mirror his fathers relative success in regards to foreign policy? What do you think lead to Bush Sr being rather succesfull, and Bush Jr so ineffective?