Age Versus Ideology
Whenever pundits try to form an all-inclusive storyline for what is currently happening in the world of politics, they usually are forced to ignore situations that cut against the grain. It's inconvenient while trying to explain "the voters are feeling X right now" when you stumble upon an individual contest where the voters are doing exactly the opposite thing. As Al Gore might say, sometimes you have to deal with inconvenient truths.
I certainly don't exclude myself from that statement -- at times, I've been just as guilty as other pundits of buying into a sweeping storyline that attempts to take the pulse of the American voter while brushing off data that directly contradicts such a storyline. Which is why it is worth pointing out that today's Democratic primary race in Massachusetts seems to be one of those "doesn't quite fit the conventional wisdom" types of races.