National Security? I suppose anything is possible but given today's technology and "global" military/CIA, if they depend on the US wired or cell infrastructure to keep us safe, we should all be scared. These resources did not provide even one square mile of coverage in Iraq or Afghanistan.
I was watching a NatGeo (or Discovery?) program about Air Force One and while it inter-links to the land and wireless networks, it uses satellites. I'd also bet that the down-link interconnects are ridiculously redundant and strategically placed. I also expect this is the norm for other branches of government that deal with matters of national security.
Communications is a critical infrastructure sector and is a national security issue. National security isn't just provided by DoD and CIA and it isn't just conducting operations in Iraq and Afghanistan.
My bad. I didn't know national security had such a broad definition. I was thinking external threats to our sovereignty and it's really any threat that would have significant impact on America's way of life.