You're seeing that bit of information as evidence that he can -- I'm seeing it
as evidence that he won't. Later, we see the Nine do just that, take control of
Frodo's mind. So, what distinguishes between good and evil? The power? Or the
use of the power?
Another reason it likely isn't Gandalf is that he's wandering around Fangorn,
"heavy with thought, and weary after my struggle with the Eye of Mordor."
And I agree about the significance of Aragorn giving Pippin the brooch, but is
it so important that a divine power intervenes to make sure that it
happens?
