At its most base level, I think no one can dispute the fact that al-Qaeda, which clearly launched the attacks of 9/11 and schemed a number of other attacks afterwards, has been, if not decisively defeated, certainly spread out, and is now on the run. It has morphed into a different kind of threat, if you will, but it certainly does not represent the geographic locus and nexus of planning, capability, and fundraising that it once did. That action in particular, in that limited sense, absolutely has affected the defence of North America.
On April 10th, 2014. See this statement in context.