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... can we make it official??
It's the person's self-interest and proximity to these documents which leads me to trust him/her for this limited purpose.
-- GlennGreenwald
Indeed, and I would say that the fact that whistle blowers, if we're to put this source in that category, generally work AGAINST their own self-interest, endangering their positions and treatment within their organizations, is why there is significantly more latitude in how much these sources can be trusted, in comparison to the punditry/on-air lobbyists.