Cindy Sheehan--When is it "Mission Accomplished"?

I was in my late teens and twenties during the Vietnam war. My father was opposed to the war but I remember he became very frustrated with anti-war protestors. I can't know if Cindy Sheehan's real purpose was to meet with George W. Bush but somehow I doubt it. She has become a brave symbol for those opposed to the war and gained a great deal of support but when does she become "stale" news and her vigil become counter-productive? That is a real danger. I don't know the answer but I hope it is a question people are asking. Something to think about.