The 2008 election was a reminder of the demographic forces that are changing America and potentially the political balance in the country. The most diverse electorate in the nation's history added to the favourable winds that pushed President Barack Obama to victory. He will need the assistance of those shifts even more in 2012 if he is to avoid defeat.
Much has been made of Obama's unusual coalition in 2008 - huge turnout and overwhelming support from African Americans, the backing of Latinos, the energy of younger voters, the help from college-educated Americans and the role played by unmarried women. Part of Obama's success was due to the excitement his candidacy generated among these groups four years ago, but part too owed simply to the realities of a nation changing in ways that are favourable to the Democrats.
The tension Obama and his advisers will confront next year is how much those inexorable demographic changes are able to overcome the effects of the economy on many of the voters who elected him four years ago and the backlash to his policies among many voters.
Two analysts from the progressive Centre for American Progress, Ruy Teixeira and John Halpin, have provided the most comprehensive examination to date of how those factors could affect the vote in 2012.
The analysis is called "The Path to 270: Demographics versus Economics in the 2012 Presidential Election."
The study examines whether the electorate in 2012 will be shaped more by the demographic changes coursing through the population, or by Republican enthusiasm to defeat Obama.
In an exclusive partnership with The Washington Post.