This is probably a toss up now. Only the weakness of Buck made it lean D.
The weakness of Buck made it Likely D.
Seriously. Remember when PPP was the only pollster that had Bennet beating Buck in 2010? Colorado will come home at the end.
I think Udall is the slight favorite, but I'm obviously biased so I'll just give my full take on it.
As I said in the other thread, I suspect we're not going to have a good idea of who the winner will be
at least until the week of the election. Gardner's advantage here is that he's not Ken Buck. Udall's advantage is that it's not 2010, and even if it was, Gardner is still pro-Tea Party and has a voting record to show for it. I would not be surprised if we were to see this race called the morning after the day of the election. But, I think the fact that Bennet was able to keep his seat four years ago speaks to the strength of the demographic changes of the state and the way the Democrats organize there, and obviously Colorado has not gotten any whiter since then.
The fact that this is an Obama state that didn't swing more than a point or two against him helps, as well. In fact, I think this is one state where an Obama campaign appearance would help the Democrats, and not hurt them. The Dems have a built-in floor in this state now - a "firewall" - but that can obviously be broken if voters aren't mobilized.