"The impetus for the song had come as James Taylor teetered on the brink of impending stardom, as she described: I was watching his career and I was thinking that as his woman at that time I should be able to support him. And yet it seemed to me that I could see the change in his future would remove things from his life. I felt like having come through, having had a small taste of success, and having seen the consequences of what you think it's going to give you-well, I just felt I was in no position to help. I knew what he needed was someone to support him and say it was all wonderful. But everything I saw him going through was ludicrous, because I thought it was ludicrous when I'd done it. It was a very difficult time and the song was actually written for that person: 'In the office sits a poet and he trembles as he sings and he asks some guy to circulate his soul around........"
Taken from Karen O'Brien's S&L biography on Joni. Don't know the source though. If you want to read more, you have to buy the book, right Karen?