Election expert Jay Cost makes the excellent observation that, four years ago, Hillary Clinton and Mitt Romney led in early polls of the Iowa caucuses. The eventual winners, of course, were Barack Obama and Mike Huckabee. Cost says: “[T]he nomination process as we know it today has produced surprising nominees time and time again since it was first implemented some 39 years ago – George McGovern in 1972, Jimmy Carter in 1976, Bill Clinton in 1992, John Kerry in 2004, and John McCain in 2008. At this point in each cycle, nobody really saw any of these guys taking the top prize.”

The reason, Cost explains, is that primaries ask more of voters. Typically, a voter makes his decision based on party identification. But when the fight is within a party, he needs more information on which to base his choice. Gathering that information takes time. Which is why we won’t know the true landscape of the primary fight until late, late in the game. In December 2003, everyone thought that Howard Dean was going to steamroll Dick Gephardt in Iowa. Instead, the two candidates destroyed each other, leaving space for John Kerry’s late surge.

Rather than obsessing over every last detail of the horse race, one should pay more attention to the fundamentals: Do voters respond favorably or unfavorably to a particular candidate? Does the candidate have enough money to pay for television when the primaries go national? Does the candidate have an actual message—an answer to the question of why he (or she!) is running for the presidency, and a realistic agenda for what he wants to do if he wins? Does the candidate seem “appropriate” to the most important job in the world?

Thinking about such questions will help us narrow down the list of serious competitors. In the end, though, the future in politics is never a straight-line projection of the present. Mitt Romney and Michele Bachmann are off to a great start. But Cost is right: The race is far, far from over.