Take a look at this chart of the performance of Hillary Clinton and Barack Obama in the different age groups measured by exit polls, and then think about this question: What does this chart have to say about which candidate would perform better in a re-election race in 2012?

Those young voters who chose Obama so overwhelmingly over Clinton are going to be in the ascendancy four years from now, and the older voters upon whom Hillary Clinton now depends will be smaller in number.

Keep in mind that these are just results from South Carolina, and that exit polls are not completely accurate, and that a presidential candidate should be chosen for ideals, and not strategy.

Still, the chart does give one pause, a pause in which reflections about the future of the Democratic Party are quite natural.