Vulnerbilities of Interconnection

Or you cut the lines coming into the city - i.e Chicago has about 5
diverse routes for fiber into the city. No explosives required and you
get the same effect.

The early ideas for the arpanet/internet never said every point would work
under all conditions. The premise was if you destroyed (which implies
something is in fact destroyed) part of the network, the surviving parts
of the network could function. It said nothing about the ability of the
part of the network which was destroyed to function. It may be obvious
the destroyed portion of the network will not function, but sales people
don't always go out of their way to explain the concept.

  The Paradox of the Secrecy About Secrecy by Paul Baran, August 1964
  The overall problem here is highly reminiscent of the atomic energy
  discussions in the 1945-55 era--only those who were not cleared were
  able to talk about "classified" atomic weapons. This caused security
  officers to become highly discomfitured~by the ease with which
  unclassified clues were being combined to deduce highly accurate
  versions of material residing in the classified domain. This points up
  a commonly recurring difference of opinion (or philosophy) between the
  security officer and the technically trained observer. The more
  technical training an individual possesses, the less confidence he
  seems to have of the actual value of secrecy in protecting the spread
  of new developments in a ripe technology. True security does not always
  equate to blanket unthinking secrecy. While the security value of
  effective secrecy can be high, we must be realistic and acknowledge the
  constraints of living in a free society where effective secrecy in
  peacetime is almost impossible. Avoiding a touchy subject by falling
  back on edicts rather than rationality may automatically insure the
  continued existence of the touchy subject.