Sauron Diminished?

[Lalwendë]

Hmmm, maybe there is a much more simple explanation than the one I offered earlier.

even if he did not wear it, that power existed and was in "rapport" with himself: he was not "diminished."

It's quite possible that Tolkien is here referring to the fact that nobody else could use the One Ring, that only Sauron could use the power within it to the full, and that if anyone else used it, then the "rapport" would mean that ultimately, they would be doing Sauron's work. Or does it mean that both powers existed in parallel?