The way our brains work, we attempt to apply a narrative or causality to events, even after the fact, to justify what happened and why it happened. We look for points where the momentum shifts and where all of a sudden something that was unthinkable becomes inevitable.
Baseball is full of these moments. Of course Jeff will tell you all about game 6 of this year's World Series and no one will ever stop talking about the Bartman play in Chicago or Buckner's famous muff. Teams didn't win or lose on those plays but it changed the flow of the game and, in retrospect, we consider it to be the dramatic reversal in the narrative.
Politics follows a similar course. In the 2008 Democratic primary, Hilary was inevitable but then Obama won Iowa and the narrative shifted. Sure, the changes may be due more to organization or groundwork but we prefer the grand, sweeping narrative and we look for game-changing moments.
This week's Republican debate in Michigan offered the new narrative of choice for the primary season: Perry's final flub. For a campaign that had already hit a rough patch (polling behind Herman Cain? Seriously?), they needed a strong showing. Here's what they got:
Granted, the last time a Texas governor became president, serious doubts surrounded his mental capacity. And some pundits even point out that Perry's damage control may have helped humanize him for the voters. But if Perry does end up losing the nomination as now seems likely, the narrative will state that this moment was what nailed shut the coffin. That's just how our brain's work. And how Perry's didn't.