Three politically relevant conclusions follow from these data. First, Democrats’ greater diversity means that party leaders are bound to have more trouble managing their coalition than the Republicans will theirs. Second, the Independents who helped Democrats score a notable success in the 2006 midterm elections may well do the same for Republicans in 2010.

The third conclusion to be drawn from the poll is that, whether Democrats lose control of the Congress or remain in power with much narrower majorities, Obama’s challenge will resemble the one Bill Clinton faced after 1994—namely, reestablishing his standing among those voters outside of the Democratic base whose support spells the difference between retaining and losing a national majority. I’m not necessarily suggesting that Obama should do that the way Clinton did, by championing small-bore issues—such as school uniforms—designed to send reassuring messages to the electorate. But I am suggesting that he should bring comparable focus and clarity to the task of broadening his appeal beyond his core supporters… and organize his White House to maximize the chances that he can accomplish that task.