It is not futile to point-out where we went wrong in this election cycle. Opinion: we picked the most moderate candidate to run for president. Further, Kerry attempted to appeal to more right-leaning voters by being pro-war and refusing to discuss progressive issues at all. This demoralized the younger voters and our base was not as energized at it needed to be, and the GOTV effort was simply not as good as the GOP's.
In retrospect, Kerry's weakest point was that he voted against the funding for the war after he voted for the war. Senators are weak by nature because, if they are good, they must vote in context and when the opposition removes that context, the indiscerning voter sees a "flip-flopper".