Lúthien Tinúviel & the Istari

[Inziladun]

Originally Posted by Formendacil

Hmm... my inclination, right at this moment, is to say that the Istari weren't restricted, even juridicially, in how much power they could use in Middle-earth (hence when Gandalf fights the Nazgûl or the Balrog, he's letting loose), but that the rule was more that they had to maintain the charade of being Old Men, which would, of course, cause a certain amount of caution. I mean, it's only from the extra-LotR texts that we know the Istari are Maiar, and even when Gandalf's returning to West, it's still not clear what he was when he left there.

I think the fact that Gandalf the Grey's greatest displays of power (when he fights the Nazgûl and the Balrog) occur when there is no one else to witness is significant. The Istari, is is said :

were forbidden to match [Sauron's] power with power, or to seek to dominate Elves or Men by force or fear.

ROTK The Tale of years

There was nothing wrong with their bringing the full range of their powers to bear in an emergency situation, but doing that in view of the Free Peoples of ME could lead too easily to the will of the Istari being done due to awe and fear, and not out of wisdom.
That said, Gandalf was possibly close to crossing the line when he threatened to 'uncloak' before Bilbo, in order to loosen the Ring's hold over him. Luckily, Bilbo took the hint.
Melian was under no such restictions. In order to remain true to the Music she was obligated to use discipline and her own sense of 'rightness' when utilising her diving powers, and she seems to have done a masterful job.