[Mithalwen]

This is a good point especially since, in one of his last writings on ME Tolkien concluded that Glorfindel WAS the same person as Glorfindel of Gondolin returned exceptionally, on release from Mandos, to middle Earth quite probably specifically to aid in the fight against Sauron.....

And such was the power of Glorfindel that there is no doubt that he could have taken it had he desired it when Frodo was so vulnerable ....

It seems to me, in Middle Earth as in our own world that some have more desire for power than others - Glorfindel, while being mighty and valiant seems to have this in common with Elrond and Faramir that he did not desire power on his own account...