"A pro-defense, pro-individual rights, pro-freedom centrist Democrat could have walked away with this election".
The reason they won't do what you suggested is that they are not centrist, pro-defense, pro freedom or any of the other things you describe.
The party, that I used to be a part of, has been hijacked, piece by piece, by a conglomeration of special interests. So concerned about trying to regain power and control over budgets, they now stand for no one.
A lot of groups, Unions, African Americans, and others seem to blindly support a steady parade of rich, white, power brokers running the party for their own personal power and aggrandizement rather than on some principles or core beliefs.
The Republicans are only slightly better in that they do seem to have some core beliefs that they stick to, (most of the time) and are smart enough to understand you can't appeal to everybody about everything or promise to buy the world a Coke on someone else's money.
They had exactly that kind of candidate in Lieberman, not the Lieberman that ran with Algore, but the guy that had been hanging around the Senate, speaking his honest mind for years.
He was literally laughed out of the primaries by the hard core lefties now running the party.
Go over to DU, when your stomach is feeling stronger, and take a look at what Democrats said about this guy when he was running. He has been accussed of being part of the VRWC and in Bush's pocket all year.
Bush has polarized a lot of people in part because he doesn't seem to stick his finger up every twenty minutes to see which way the wind of public opinion is blowing. He makes a decision and goes with it.
It may be hard for some folks to recall, it's been so long, but that is what the President is supposed to do.
