William Galston is back at it, warning the Democrats that they ignore polling data at their own peril. Looking at the recent Pew poll, he explains:

On the whole, 58 percent of voters see Democrats as liberal or very liberal, while 56 percent see Republicans as conservative or very conservative; no surprise there. But voters now place themselves much closer to the Republican Party than to the Democratic Party on this left-right continuum. Indeed, the ideological gap between the Democratic Party and the mean voter is about three times as large as the separation between that voter and the Republican Party. And, startlingly, the electorate places itself a bit closer to the Tea Party movement (which is well to the right of the Republican Party) than to the Democratic Party.

As he notes, this is a “major shift from five years ago” and a warning signal that Independents “who helped Democrats score a notable success in the 2006 midterm elections may well do the same for Republicans in 2010.”

Democrats have been reluctant to draw the obvious conclusion from this very stark data. As a result, they’ve not adjusted their agenda or moderated their rhetoric to arrest the Independents’ flight from their party. They prefer to increase the volume on their anti-Bush, anti-conservative vitriol. That — of course — only deepens the disaffection of Independents, who generally loathe partisan nastiness.

Galston advises Obama to think hard about “broadening his appeal beyond his core supporters,” but that would require an acknowledgment of failure and a dramatic re-orientation in his big-government liberalism. Perhaps the shock of an election wipe-out will do the trick. But for now, the Democrats remain stubbornly indifferent to all warning signs and reasoned advice.