Aragorn's assertiveness

[Kuruharan]

Apparently, I must spread some reputation around before giving it to Boromir88 again.

Practically, of course, it would have been ridiculous for Aragorn to try to undo Rohan's sovereignty.

However, I still hold my original opinion that Aragorn, as legal matter, could have revoked the Oath because of the clause of the Great King returning.

Originally Posted by Boromir88

Similarly, as Aragorn, being Isildur's heir is the judge over the King of the Mountain fulfilling his peoples' oath to Isildur.

I don't see this as being the best parallel because Isildur was sovereign himself (or was he? When exactly was the curse cast?) Cirion was only a servant, exercising power explicitly because of the absence of his master.

Which is why you have Gandalf there to mediate, and tell Aragorn as silly as Théoden's demand is, he will have his own way, in his own hall and land.

As being, literally, a representative of the Valar, perhaps it could be interpreted as Gandalf giving their opinion on the matter.