What's the hot topic?

I teach modern US history, 1865 to the present. But I do it in a pretty cool way. We go backwards. After an initial unit on basic civics, I begin with the current day and go backwards about a decade at a time (the units get both broader and less deep as we go). Although I update my lessons every year, it's pretty much guaranteed that my 1920's lessons are not going to change that much. However, the most recent stuff needs to be almost totally overhauled every year. I remember when the 2000 election and 9/11 necessitated an almost complete rewrite of the "conventional wisdom." More recently, a couple of years ago the Supreme Court and judicial filibusters were the hot topic. Last year it was the surge in Iraq, with a nod toward the early primary season (it seems a long time ago that John Edwards or Rudy Giuliani seemed key figures in a history class). Obviously, this year the general election will merit attention. But it's really interesting to me how some stuff that everybody knew was going to be important even a year ago can flip in a heartbeat. I would have bet a good sum last year that the 2008 election would be a referendum on Iraq. But not only has the success of the surge taken some of the urgency out of the topic (and the candidates have edged closer and closer together in their positions), but nobody foresaw $4 gasoline. The only thing I know for sure is that I have no idea what will be THE big issue come November!