[The Squatter of Amon Rûdh]

No need to thank me; it's harder not to express my opinion. At great length.
That's just something that occurred to me as I was re-reading LoTR this latest time. It seems to me that nowadays it's considered somehow weak for a woman to behave as Arwen does, but here's why I think she comes out as a strong character: Unlike Eowyn, Arwen isn't skilled at arms, and going along with Aragorn would only distract him with worry about her welfare. He needs to know that she's safe to keep his mind on the job and I don't doubt that she knows that. It would be self-indulgent and incredibly stupid to try and go along, so she stays at home.
What's also impressive about Arwen is her constancy, which isn't a trait that I see very often outside books: she's prepared to wait for decades while Aragorn does what he has to do to help save the world. It would be pointless not to accept it, since he doesn't really have a choice, but a lot of people would still complain and issue ultimata, perhaps even call the whole thing off. Instead she helps where she can by making his royal standard. This doesn't seem so important to a modern audience, but in a medieval army the standard is the focal point, enabling soldiers to find the general in the confusion and representing the army's pride and sense of purpose. One might even call it the army's heart and soul, which is why so many standard-bearers are killed on the Pellenor Fields. Also imagine the King's force coming up the Anduin without a flag to identify them: that could have been nasty.

It's this wisdom and spiritual stamina that make Arwen such a good character, however small her part may seem to the uninformed. I don't think that Aragorn could have kept going without her.