In my opinion, Cong. Issa of CA line of questioning during the hearing before the House Oversight Committee, was the most poignant of all. I was not able to view the entire hearing so there may have been others who asked pertinent questions.
I believe Holder has been caught in a lie. He claimed that he only learned about the Project Gun-walker a "few weeks ago". He also attempted to brush off criticism by Issa with talk about ongoing investigations and a classic Clinton-speak; "I felt their pain."
Today during the Senate hearing the only person who asked any questions about this scheme was Grassley and as far as I am concerned he is useless. He can't even read the notes effectively.
Now we need to see what happens. Can Issa prove that Holder is lying? and if so what happens next? Will the cover-up continue in the wake of the AG testifying that he intends to fully cooperate? Will anyone at ATF be punished?