Doesn't the buck stop with Hillary?

Umar Farouk Abdulmutallab "The Underpants Bomber" had a U.S. visa that had been granted in June 2008 and was valid through June 2010. The visa was issued in London.
The U.S. State Department is responsible for visas.
Dr. Umaru Abdul Mutallab went to the U.S. Embassy in Abuja, Nigeria and gave them the heads-up that his son was a terror risk.
U.S. Embassies are operated and controlled by the U.S. State Department.
Hillary Clinton is in charge at State. Isn't that where the buck should stop?