The story begins at 36:42 into the video, if my Youtube-fu is weak. The Official Secrets Act was used, not to prevent the Soviets (and Warsaw Pact, and Red Chinese) from getting excerpts of the book "Spycatcher" from retired MI6 operative Peter Wright; all of these commie Intelligence Agencies already had copies of the book. Everyone in the USA or Canada who wanted to had read the book. The Act was used punitively, to keep Her Majesty's subjects from reading something that would embarrass the Government.
This was a quarter century ago, and l'affair Snowden shows us that the USA now effectively has an Official Secrets Act. One frequent defense of the NSA is that "everyone knew that NSA was spying on Americans". That's wrong, as repeated NSA attempts to keep this information from Congress show, but assume, arguendo, that it is true - it was widely known that NSA was spying on Americans. If so, then what possible use comes from suppressing the information Snowden leaked? After all, if everyone knew, then al Qaeda knew, and the only upside to suppressing the information is to make the politics run more smoothly.
Hitchens' entire discussion is fascinating, as a foreshadowing of what has descended on these shores these last twelve years. It's quite an upside down, mixed up surveillance world we find ourselves in where the Director of National Intelligence uses the "least untruthful" words in testimony to Congress.
“'When I use a word,' Humpty Dumpty said in rather a scornful tone, 'it means just what I choose it to mean - neither more nor less.'”
- Lewis Carrol, Alice In Wonderland