The real key is getting the massive amount of people who don't vote, to vote. I think most Americans would agree with Democrats' platform. However, the GOP has been very effective in suppressing voters, as noted in the following article regarding Obama's voter registration efforts. Even a modest increase in voter turnout could help, not only Obama, but Democrats across the board.
http://www.thenation.com/doc/20080901/hayes/snip
Given all this, one would think that a new voter approach would be a no-brainer for Democrats. But it turns out that transmuting nonvoters into voters requires a tremendous amount of painstaking labor and a massive volunteer mobilization that few campaigns have the financial or organizational resources to pull off. Indeed, before Iowa, old hands were scoffing at Obama's plan to rely on new voters, particularly the young. But youth turnout in the caucus doubled, and young voters turned out (perhaps for the first time in American history) at the same rate as senior citizens did. Clearly, the Obama campaign had figured something out that others hadn't.
/snip