John Kerry lost in 2004 because he didn't run as the John Kerry of 1971. He didn't oppose the Anti-Muslim War, he didn't oppose the Patriot Act, and he didn't support any significant new domestic programs. His whole pitch could be reduced to what he said on the Iraq War in his convention speech at the 2004 DNC-the one where he had the peace movement hived off in a "free speech zone" ten miles from the convention- could be boiled down to the words "we can do it better"- a phrase which could only be taken as a promise to change nothing- and "ready to serve", which are the same words they print on cans of beef stew.
The only sustainable future for the Democratic Party is to start running FOR, not AGAINST- to actually try, for the first sime since the 1960s, to win the argument.