At its best, it is simply the left arm of healthy governmental curiosity. It brings to a strong government what it needs to know. It’s the collection of information, a journalistic job, if you will, but done in secret. All the rest of it—intervention, destabilization, assassination, all that junk—is in my view not only anticonstitutional but unproductive and silly.
Source: Paris Review – The Art of Fiction No. 149, John le Carré