But having read about JRR's publishers apparently NOT being thrilled with what he'd written towards The Silmarillion, it brings a question to my mind. Having written Luthien as such a powerful being, and really a leading character, is it possible that the female roles in LoTR were diminished by editorial decision? Yeah, Galadriel is also powerful but her part is small. And yes, Eowyn did finally make a noteworthy appearance in Return of the King, but I'm re-reading Two Towers and she was left behind completely in the entire Helm's Deep saga. When you think about the time when these books were written and published, I can't help but think Luthien was rejected in favor of Arwen, who (in the book at least) is just a beautiful Elf-maid that doesn't really do anything. I know she's not popular, but this thought makes me appreciate Tauriel all the more. She seems to reflect the spirit of Elwing, who took flight and searched for her love Earendel. But maybe that's just me. Anyway, I gotta go sit with a sick grandkid, so I probably won't be doing any more reading today.

Arwen left the Elessar with Galadriel. She did not send it, but left it. That is a crucial difference. Arwen has not been in Lothlórien for nine years. She foresaw that Aragorn would pass through Lothlórien, when it was time for him to claim his birthright.
[cut] Aragorn's two different reactions are significant. He dismisses the Paths of the Dead when Elrohir mentions it, but after finding out about the standard, he starts contemplating it deeply. He continues to do so for the rest of the night.
[cut] No one (at least no one whose alive) can see anything on the standard. And yet, it convinces the dead that Aragorn is truly Isildur's heir, as they decide to follow him. Even in the middle of the night, light should have reflected the banner, with those descriptions. We know that Mordor's shadow was not over them yet, since it says “the dawn came, cold and pale.” So an enchantment must have been at work, that night with the dead. There is no need for an enchantment to convince the living, as any help will be celebrated in the midst of a battle.
Elves have the ability to put their power and intent into the things they make (see more here). Arwen spent ten years making and imbuing it with her power, using priceless materials.
[cut] The standard is twice referred to as “the standard of Arwen”. Her power and achievement is clear.
[cut] Rumor has already spread throughout the city, that the King has returned. Aragorn proudly displayed both his standard and Andúril on the battlefield. Ioreth tells us that, “For it is said in old lore: The hands of the king are the hands of a healer. And so the rightful king could ever be known.”
Two times we are told that there is a prophecy stating that when Aragorn becomes king, he will bear the name Elessar, meaning Elfstone. The prophecy seems to have been made at his birth, and Arwen clearly knows about it. She knows that this Quest is where Aragorn will claim his heritage, where he will finally stand forth as the rightful heir to the throne.
She also must know the lore that says, “The hands of the king are the hands of a healer”. Her gift of the Elfstone has a clear purpose – Aragorn fulfills the lore that says the true king is a great healer; which in turn causes his people to not only recognize him as the king for certain, but to ask for his help in healing their loved ones; which by healing their loved ones causes Aragorn to become beloved by his people; and that prompts them give Aragorn the name Elessar/Elfstone, thus fulfilling the prophecy.
In short, by giving Aragorn the Elessar, Arwen insures that not only the prophecy becomes fulfilled, but also that the people are on Aragorn's side, as the Elessar gives them something to latch on to and idealize Aragorn with. I'm sure we can all imagine what would have happened if Denethor had lived, and Aragorn had had no connection to the people. It would not have been pretty. This way, even if Denethor had lived (and they had no reason to think otherwise), his political power would have been much less – Aragorn already had the favor of the people.
So. Between the standard and the Elessar, Arwen gives Aragorn the tools he needs to convince men (both dead and alive) that he is the rightful king. That is on top of training his horse, so he has a trusted mount in battle. Her political acumen is great. It is clear – Aragorn could not have become King without Arwen.
[cut] Arwen's wisdom, and her ability to see deep into the hearts of others, is not restricted to Aragorn. She plays one more vital role before the end of Return of the King.
[cut] Where does Frodo come into this? During all of this chaos, Arwen picks up on the fact his wounds have not really healed, especially on the Unseen plane. No one else has noticed this, but Arwen has. As the text says, she arranges a gift for Frodo. He will be able to sail to Valinor, and find healing.
Sail to Valinor. No mortal has ever had permission to come to Valinor. It would not be easy for Arwen to get permission for Frodo, but she could try. She almost certainly went to Gandalf, as he is the only emissary of the Valar that she knows. Arwen tells us that she used her own choice of choosing not to sail as leverage. As this essay shows, both Arwen's and Frodo's choices were entwined. Arwen's choice to become mortal helped restore the Age of Men, and Frodo's choice to go beyond the point where healing would be possible saved the world he loved. Frodo's choice also gave Arwen the chance to make her choice – no end of Sauron, no life with Aragorn.
Knowing all of that, Arwen proposed an exchange, saying that Frodo deserved a chance of healing and peace after everything he had done. We know that Gandalf accepted her plea, and that Frodo got to sail.
[cut] It wasn't enough for Arwen that Frodo would eventually find peace and healing in Valinor. He would still have to suffer in the present.
To aid Frodo now, Arwen imbues a gem with healing power. It is not a permanent fix, only a temporary relief. But it is enough for now, for she has already arranged for him to take the permanent fix, if he wishes it.