The latest Gallup report, based on a massive sample of more than 39,000 adults, contains troubling news for Democrats. Individuals identifying with the Democratic Party are a smaller share of the American people than they were early in 2008, and their views are less representative of the people as a whole. This means that the Obama team, which faces the crucial choice of either doubling down on its 2008 winning mix of professionals, young people, and minorities or rebuilding support among Independents in the heartland, should emphasize the latter option. Any general election strategy that relies solely on mobilizing the party’s diminished base will have a hard time forging a majority of the popular vote.