On his blog, Dick Polman of the Philly Inquirer takes a sharp look at the Dems' "trouble on the left flank:"

The Democrats on Capitol Hill clearly face a difficult challenge. The liberal activists within their ranks are anxious to advance what they see as the moral rightness of their positions, notably a de-funding of the Iraq war. As Sheehan said yesterday, "These are not requests. These are demands." And as Deborah Sweet, who runs a pro-impeachment group, said the other day, "We've been told for many years, 12 years now, 'Wait until we get in power. Then you'll see things change.' We'll give them a couple of months or a few weeks to see what they come up with, but if they don't do something very decisive around the war and these other issues, I think there will be trouble." [snip]

The Democrats broadened their tent in the '06 elections; they captured 59 percent of all independent swing voters. Whether they can hold those voters over the next two years, while satisfying the shouters on their left flank, is another issue entirely. They probably can't snag the White House in '08 unless they find a way.

Sounds about right to me.