[Alcuin]

I think that after his return from physical death, Gandalf had a few new things to deal with. One of these was certainly Saruman: like Sauron, Saruman had become a rogue Maia, and the ultimate ruler of the Maiar – Eru – was responsible for Gandalf’s return. Saruman was given “a last choice and a fair one: to renounce both Mordor and his private schemes, and make amends by helping” the West. (TT, “Voice of Saruman”) He refused: “He will not serve, only command.” (ibid.) This is pride, and if we look at Lord of the Rings as a Catholic book for a moment, pride is the first, primordial sin.

Originally Posted by Galadriel55

Saruman "renounced" his colour, but wanted to keep the rank assosiated with it. Maybe by breaking his staff Gandalf showed him that its either none or both.

I had not considered this before: Saruman willfully, knowingly, deliberately and repeatedly broke the rules under which he was supposed to act. What necessarily followed was his dismissal “for cause”.

Originally Posted by Galadriel55

I find it curious how Gandalf only has the power/authority to break Saruman's staff and kick him out of the order when he becomes white. It could be because until that time Saruman was still superior to Gandalf, no matter how corrupted he got. It is possible that when Gandalf was sent back he received more power/authority that Saruman had, or at least the same amount. An inferior can't kick out his boss, but an equal can kick out an equal.

I agree. Gandalf the Grey did not have the authority to act against Saruman, who was his superior in the Order of the Istari. Gandalf the White did have that authority, and apparently had been charged to deal with him.

Originally Posted by Formendacil

On the side of "all wizards need staves," I'd like to just make the semantic quibble that Gandalf is singled out as using a staff, as needing a staff. ...

On the other hand, however, I wondered... if Gandalf is the only one with a staff on arrival, why did Saruman pick one up in the meantime? Clearly, not just because he got older, because Gandalf removing it is a major problem for him, and not because he needs a crutch.

The thought that occurred to me, reading all this, was that maybe it is because the staff belongs with the Keys of Orthanc--part of his badge of office as the steward of Gondor's power in their far-flung tower. ...

...[T]hat brings up the legal question of how Gandalf could deprive Saruman of a Gondorian office... Another could assume that Gandalf has Aragorn's implicit consent...

Gandalf’s Dwarven name, Tharkûn, was said to mean “Staff-man”. He is the only one of the Istari in the Unfinished Tales essay that I can find who is mentioned carrying a staff.

The symbol of royal office in both Arnor and Númenor was a scepter, a kind of staff or rod; and the rod of office of the Lords of Andúnië was used as the Scepter of Annúminas, the royal scepter of Arnor that Elrond returned to Aragorn before he gave him the hand of Arwen.

As for Gandalf’s acting as Aragorn’s chancellor or prime minister, that seems to be their implicit agreement up to “The Last Debate” of the Captains of the West, and the explicit command of Aragorn from that point onwards until Gandalf “resigns” that post at the hallow on Mount Mindolluin when Aragorn finds the sapling of the White Tree. Aragorn does not seem to have wanted to reveal himself to Saruman (at the time, neither he nor Gandalf knew for certain that Saruman had been communicating with Sauron using the Orthanc-stone, though they might have guessed), so at least in demanding from Saruman the Keys of Orthanc, Gandalf was surely acting as Aragorn’s agent; nor could Denethor have objected, since Saruman in Orthanc posed a threat to Gondor’s defense.

It may be that Gandalf had more authority than either Aragorn or Denethor, but his leeway to exercise that authority was closely circumscribed. After all, Saruman’s ignoring the circumscription to his authority is why he was cast from the Council and the Order. The Order of Istari (UT, “The Istari”)

were forbidden to reveal themselves in forms of majesty, or to seek to rule the wills of Men and Elves by open display of power, but … bidden to advise and persuade Men and Elves to good, and to seek to unite … those whom Sauron … would endeavor to dominate and corrupt.