I found this article in today's Denver Post particularly interesting. It describes the simultaneous evolution of both Mark Udall and the state of Colorado. In 2004, when Sen. Ben Nighthorse Campbell decided to retire, Udall immediately threw his hat in the ring. Top state Democrats thought Udall was too liberal to win, so they pressured him out of the race and recruited the more moderate Ken Salazar to run.
This year, with another open Senate race, Colorado Democrats think that Udall could actually win. Not only has the state become bluer, but Udall has shored up his moderate credentials with a stint on the U.S. House Armed Services Committee, even though his House district contains no military bases. So the party cleared a path for him and assured him the nomination.
Interesting to see a party moving toward its ideological extreme as it becomes more confident in its position.