Colorado Colorado Colorado

If you locked me in a room until election night, and then made me guess the electoral winner using only the knowledge of one state's winner or the national popular winner, the question I would ask is not "Did Obama win the national popular vote?" The question I would ask is "Did Obama win Colorado?" That's how important I think CO is.

For some time now, CO has been at the top of my list of swing states, with only MI occasionally appearing to be nearly as important. Because the blue-to-red ranking of states is highly stable, and because CO is currently the clear electoral tipping point with only six weeks left to go, I've argued here, in a comment here that there is a small number of states that matter, and that CO is at the top of that heap.

It's nice to see the conventional wisdom and top-shelf bloggers are advertising the importance of CO, and that the Obama campaign is putting offices throughout CO.

Here's a graph of how much Obama's lead in CO exceeds his national lead, over time throughout 2008, with 3σ confidence bounds. Polls were infrequent early in the year, but it's clear that Obama picked up about 0.25% in CO relative to the US recently (probably because of the Denver convention). This is a big deal, because it gives Obama a slight advantage in the electoral college. Recall that Kerry had a slight advantage in the electoral in 2004, but that the electoral college has looked neutral to me, because of Obama's huge gains in deep-red western states. Now Obama has roughly a 70-80% chance of winning an election if the national vote is tied, which translates roughly into a 4% extra chance of victory. In other words, the fact that the Democrats held their convention in Denver gives them a 4% extra probability of winning, compared to holding their election in a random spot. Combine this with the tepidity of CO Republicans toward McCain, and we could easily be headed for an Obama electoral win even if McCain wins the national popular vote.

By contrast, the Republicans made even better gains this summer in MN relative to the whole country, which doesn't matter because MN is not a swing state. Both parties made pretty ballsy guesses about which states would become swing states; the Democrats guessed right, the Republicans wrong.

Off topic, but I was surprised that McCain does not have offices in the areas of Maple Grove or Woodbury, MN. MN was a state that the Republicans wanted to pick up, right? And the burgeoning NW and E suburbs and exurbs are natural places for Republicans to organize, right?

Read more (maybe)!