Democrats could not have been any more motivated. They just lost. The Republicans found a good wedge issue ("god hates fags", in a palatable euphamism sauce), and more effectively used the media to (mis)characterize their opponent.
I see a couple of options for the Dems: "If You Can't Beat 'Em Join 'Em", in which the party is dissolved and declare themselves all Republicans, kind of like the end of the (first) Matrix; or "Diaspora", in which a liberal homeland is created either through state secession, colonization, or displacment of another group (sorry, the Palenstinians have already been done).
I personally favor a Diaspora solution, since I have seen the Utopia Republicans create when unchallenged (Idaho), and would be amused to observe this on a larger scale, from a distance.