As a follow up to Jay's post below about the problems with the media's "the GOP is demoralized" consensus, this interview with RNC Chair Ken Mehlman also makes for interesting reading:

On new polls suggesting that the Republicans could be, in the words of some analysts, in free fall

Let me first say I do think that we are in a very challenging environment. I think that the situation with [Rep. Mark] Foley has made it even more challenging, but ... I have not seen a significant impact in most of the races around the country and I certainly haven't seen a free fall.

The three issues that I think we're dealing with [in the polls]: first of all is the partisanship of the electorate. In the last 25 years, the electorate has ranged from plus-4 Democrat to plus-2 Republican in '02. In the most recent poll's partisanship, USA/Gallup is plus-9 Democratic electorate, ABC News is plus-11 Democratic electorate, CBS/New York Times plus-5, Newsweek plus-8, Time plus-8, AP/Ipsos plus-8. So, every one of these polls has an electorate that looks more Democratic than any electorate has looked in 25 years.

Second, the Gallup specifically is the outlier in the change in the generic ballot. The Pew poll that came out recently showed no change in the generic ballot since the Foley scandal; other national polls have shown on average a 2-point dip, the Gallup showed a 23-point dip, which I don't think is convincing.

The third issue of course is the relevance of the national polls in predicting House races and the challenge that Democrats always have is that our voters are more efficiently distributed. You saw that in the recent battleground that came out between [pollsters] Celinda Lake and Ed Goeas, which showed an 8-point Democratic advantage on the generic ballot. But in the Republican districts that the Democrats have to win to win back Congress, it was even. In the Democratic districts, it was a 21-point Democratic advantage.

There's much more, so I encourage you to read the whole thing.