Watching the democratic primary campaigns so far, I'm struck most by the idea that the crux of the race is generational. Hilary Clinton is drawing her strongest support from older voters, and as much as they don't like to admit it, the baby boomers are now old.
Boomers don't want to be pushed aside the way they pushed aside their parents generation. Back in the 1960s, if you were over 30 meant you were regressive and too tied into the system to make change happen. By the 1980s, being over 50 meant you were over the hill and didn't understand change. Now, at 60, Hillary suggests that her experience would make her a better president than mid-40ish Obama (I'm guessing she won't bring up the fact that her husband was in his 40s when he became president). There is nothing of the outsider about Hillary.
Obama has made his campaign mantra the words "hope" and "change." This is the classic move of the young turk. The tough part for him is that there are still a lot of old turks who will be voting in the primaries.