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“Gandalf as Ring-Lord would have been far worse than Sauron. He would have remained ‘righteous’, but self-righteous. He would have continued to rule and order things for ‘good’, and the benefit of his subjects according to his wisdom (which was and would have remained great).
[The draft ends here. In the margin Tolkien wrote: ‘Thus while Sauron multiplied [illegible word] evil, he left “good” clearly distinguishable from it. Gandalf would have made good detestable and seem evil.’]
Letter 246
From a letter to Mrs Eileen Elgar (drafts)”
― Humphrey Carpenter, The Letters of J.R.R. Tolkien
The Letters of J.R.R. Tolkien J.R.R. Tolkien ,
Humphrey Carpenter (Editor), Christopher Tolkien (Editor)
Вот эти все письма оказывается можно скачать по последней ссылке и там эта цитата на с. 350