I found this paper, written in 1989, to be very interesting. It was written in a time when the Regiment was very young, and is very interesting to see the thought processes pertaining to the "Ranger idea" at the time. He brings up some great points, and I think after reading this and really thinking about it, it hasn't been until the last 10 years or so that the Ranger mission has really been defined. From what I understand, it is still an evolving concept. I think it is entirely appropriate at this point that Abrams charter be replaced with a new charter that defines the purpose of the modern Regiment. Also, I think there is still confusion even within the Regiment about exactly what the Regiment SHOULD be. Anyway, I could ramble on, but here is the article and I'm curious to see what some of your thoughts are:
http://www.dtic.mil/dtic/tr/fulltext/u2/a208204.pdf
http://www.dtic.mil/dtic/tr/fulltext/u2/a208204.pdf