The buy-back talk started happening way before the whole merger mania started a few weeks ago. It was reported in the Twin Cities news several months ago. As well as the NW service issue, CO had reportedly become concerned and resentful about NW's control, although the code-sharing and other parts of the relationship are not an issue, and CO does want to continue the partnership, especially considering NW has improved its performance over the last 4 months. In fact, if NW were to divest of the ownership, the DOJ suit would more than likely be dropped. I don't think the viability of the alliance is really an issue. It was also thought awhile back that CO was interested in a LBO (the Wall Street Journal reported this), but IMO, I think this thought has disappeared considering the vast amount of CO shares sold by executives lately (I posted a thread regarding this topic).
An unexamined life isn't worth living.