[Zigûr]

Originally Posted by TheLostPilgrim

1) If Gandalf was put into a situation where he was face to face with Sauron, would it have been permitted by Eru/The Valar, for him to uncloak himself and use the full might of his power, as we got an inkling of in his battle with the Balrog? Would that have been an acceptable time for him to "lift the veil" of Gandalf and allow the power of Olorin to be in full might?

Perhaps as Gandalf the White. See Letter 156: "where the physical powers of the Enemy are too great for the good will of the opposers to be effective he can act in emergency as an 'angel'". As Gandalf the Grey I don't think it would have really been within his purview - more appropriate to flee from Sauron than risk the kind of disastrous Ainu-vs-Ainu conflict his presence was specifically supposed to avoid. By the time of the War, however, he was operating more or less directly on behalf of Eru Himself, hence his increase in power and the reduction of the limitations imposed upon him by the Valar.

2) Could Gandalf "uncloaked" have defeated Sauron?

Personally, I don't think so. In Letter 246 Professor Tolkien observes that "It would be a delicate balance" in a conflict between Sauron and Gandalf in which Gandalf was wielding the Ring. Thus I think it stands to reason that Gandalf is only as powerful as Sauron if he (Gandalf) is using the Ring. Without this advantage it doesn't seem likely to me, cloaked or uncloaked. Regardless of how much Sauron had diminished his strength by the end of the Third Age, he was still very mighty compared to every other being dwelling in Middle-earth by that time: "I am Gandalf, Gandalf the White, but Black is mightier still." "And so am I, very dangerous: more dangerous than anything you will ever meet, unless you are brought alive before the seat of the Dark Lord." (emphasis mine) It's worth remembering that at Dol Guldur, Sauron was not overpowered but rather pretended to be so that he could fool the Council into thinking that he was fleeing when actually he was returning to his old strength in Mordor - see for instance Appendix B, the entry for 2941: "Sauron having made his plans abandons Dol Guldur." This was a calculated move. The White Council did not drive Sauron from Mirkwood: he wanted to leave, and their assault was a convenient way of lulling his enemies into a false sense of security. That doesn't prove that Sauron could have overpowered the entire Council had he wanted to, but it doesn't prove that he couldn't either. Similarly, when Sauron fled to Rhûn during Gandalf's first expedition to Dol Guldur in 2063, it would seem to me that he did so not out of fear of being overpowered by him, but rather because he did not want his enemies to learn of his identity and thus take serious action against him until he was ready. Gandalf did not discover that the Master of Dol Guldur "was indeed Sauron" until 2850. I think as a general rule there was more to his back-and-forth as the Necromancer than simply wanting to avoid having to duke it out with a Wizard.

Gandalf was one of the people of Manwe, who is equal in strength to Morgoth, whom Sauron served--This too would seem as evidence that Gandalf and Sauron were "on equal footing" so to speak.

As we've discussed in the thread about the Maiar, however, Sauron was of a "far higher order" than Gandalf (and Saruman). In addition, Manwë was not Morgoth's equal in power. According to "Myths Transformed" Manwë was "a little less great." The same text also states that Melkor, originally, "must not be able to be controlled or 'chained' by all the Valar combined", which was why he could never be fully defeated, and only defeated as a person after wasting so much of his power corrupting the earth. He was not "controllable and on a power-level with the Valar" until the Battle of the Powers. By his original nature he was much stronger. What's more, Sauron was (as we have also discussed in the other thread) originally a servant of Aulë, not Morgoth (who seemingly had no Maiar of his own), so the Gandalf/Sauron Manwë/Morgoth comparison doesn't really work.

Originally Posted by Legate of Amon Lanc

we know that Gandalf faced a quite "advanced" Maia (Durin's Bane) and defeated him.

"Advanced" in what sense, though? While undoubtedly formidable opponents, Balrogs to me seem rather diminished compared to uncorrupted Maiar, being trapped in physical bodies and unlike, say, Sauron, lacking enough spiritual vigour to remake them. A Balrog killed once seems to stay dead forever.