This NYT article suggests that Republicans may have difficulty turning their voters out this November. This WaPo article suggests that anger gives Democrats an edge. What’s more "pink is the new red".
My biggest worry at the moment is the Senate, where races tend to be closer because you can’t gerrymander states to protect incumbents. Of course, it’s only April.
Update: It occurs to me that one of the best mobilization tools for the Republicans is the angry Democratic Left. Some argue that 2006 might be a replay of 1994. Im at least tempted to argue that Democrats could turn it into a replay of 1998, when Bill Clinton and his party took advantage of anger-induced Republican miscues. (Of course, the Republicans controlled Congress then, which magnified the consequences of their mistakes, making them a little harder to overlook. But it strikes me that the Democratic Left is angrier now than most Republicans were then.)
I also wonder whether a Democratic victory in 2006 would make it harder or easier for a Democratic candidate to win the White House in 2008. Im tempted to think that angry Democrats, emboldened by a 2006 victory, would overreach and make life difficult for their 2008 standard-bearer.