Here's a senior US government official, speaking at a recent conference:

"Al Qaeda has the ability to use the virtual and physical network, all tied together in this center of gravity of this radical Islamist ideology. The fact that it uses the most advanced methods of communications to get what it needs to be done is truly remarkable."

"It has truly got its stuff together in terms of fighting as a network."

"It is a generational fight; it’s not one that we’ll see completed any time soon."

"This enemy is ingenious."