Here's the letter he sent:
It was a real pleasure just so sit and talk with you. I listened very carefully to what you had to say about this compelling history, and I’ve since read the script and found it in all the detail in which it describe these monumental events and in the compassionate portraits of all the principal characters, both powerful and moving. I can’t account for how at any given moment I feel the need to explore life as opposed to another, but I do know that I can only do this work if I feel almost as if there is no choice; that a subject coincides inexplicably with a very personal need and a very specific moment in time. In this case, as fascinated as I was by Abe, it was the fascination of a grateful spectator who longed to see a story told, rather than that of a participant. That’s how I feel now in spite of myself, and though I can’t be sure that this won’t change, I couldn’t dream of encouraging you to keep it open on a mere possibility. I do hope this makes sense Steven, I’m glad you’re making the film, I wish you the strength for it, and I send both my very best wishes and my sincere gratitude to you for having considered to me.
Guess Spielberg can't take a hint.