Sid Blumenthal has a short piece at Salon explaining the failure of his party during the last several years and what Gore's endorsement of Dean says about it.

Republican bullying has been met almost inevitably by Democratic cowering, the ruthless will to power by timid retreat. Before this spectacle, Democratic voters have felt themselves unrepresented and voiceless.

[...] In the face of constant provocation, Democrats see their own party as hesitant, compromised (if not complicit) and cowardly.

[...] Somehow, the congressional Democrats have been in denial about Bush's conservative radicalism. They preferred to believe that fundamental comity still existed even when it was being smashed.

[...] Gore now calls the right-wing media a "fifth column" within journalism, and he's raising millions to build a TV network of his own as an alternative. In his own way, he's absorbed the lessons of the past three years and become a representative Democrat. His endorsement of Howard Dean is his commentary on his campaign and the conduct of his party since.

Blumenthal himself has been smeared viciously by the right wing machine. See his reasonably well-written book, The Clinton Wars for details. I doubt he's surprised at what's gone on since Bush's selection. Until the party starts to pay attention to voices like his and the voices of hundreds of thousands of Dean (and, to be fair, some of the Clark) supporters, they will continue to wander in the wilderness, flinching everytime some Republican says "boo" and consigning themselves to irrelevant ineffectiveness.