Every rule has an exception. My mama always told me to compliment the chef at dinner. But that doesn't apply when the chef pees in your soup. Likewise, there's an exception to the rule of source protection. When officialdom uses "you-can't-use-my- name" to cover a lie, the official is not a source, but a disinformation propagandist -- and Miller and The Times have been all too willing to play Izvestia to the Bush's Kremlinesque prevarications.
And that is what Miller is protecting: the evil called "access."
The great poison in the corpus of American journalism is the lust for tidbits of supposedly "inside" information which is more often than not inside misinformation parading as hot news.