E.J. Dionne, in an item about the importance of the House special election race in NY-26, includes the caveat, "The significance of any given special election is almost always exaggerated." I actually think the importance of this race is being under-appreciated. It is just one race, and there's a third-party spoiler hurting the Republican. But the fact is that you have a Democrats surging in a Republican district. And she's not doing it by running on personality or some idiosyncratic local issue. She's running the basic template for the campaign -- attacking the Ryan budget supported by all but four House Republicans -- that Democrats will be using everywhere next year. This is a testing ground for the next election, and both sides are pouring money into what was expected to be a Republican cakewalk.
TPM has an interesting chart tracking the national generic ballot, which asks voters which party's candidate they plan to vote for in the next House race:
What does this show? It shows that the political landscape has shifted since last November. It's not 2010 anymore. Republicans can no longer enjoy the undiluted benefit of being the out party during a recession. They're sharing in power and paying a price for it.