After a historically long pre-caucus campaign, the 2008 race for the presidency is finally in gear in Iowa, and continues on Tuesday in New Hampshire, with more states to follow later in the month. And with all due respect to Freud, in electoral politics, demography is destiny.

Though Hillary Clinton is the Democratic favorite at the gate, there are five crucial demographic variables still at play that could lead to a Barack Obama (or, less likely, John Edwards) victory. As for the Republicans, these two early races come down to a sudden-death playoff of sorts for the three candidates in the hunt (Rudy Giuliani and Fred Thompson having effectively skipped these races in a risky all-or-nothing, win-it-later strategy).

Keys to the kingdom
For the Democrats, the race will ultimately depend on how these five key demographic questions are answered.

1) How many independents choose to vote in the Democratic primaries?
Clinton is stronger among registered Democrats, Obama among Independents. Thus, in primary states where Independents have the option of voting in either primary — such as New Hampshire and South Carolina — Obama needs to draw a significant number of these voters into the Democratic contest to have a chance. In a sense, Obama is waging a two-front war — against Clinton and against GOP candidates, such as John McCain, who also have an appeal to Independent voters.

In New Hampshire in 2000, roughly 60 percent of the Independents voted in the GOP primary, boosting McCain to victory over George W. Bush and dashing Bill Bradley’s hopes against Al Gore. This time, Obama probably needs at least 55 percent — and maybe more — to take a Democratic ballot.

2) Who carries the black vote, and is there a backlash?
Black voters comprise roughly 20 percent of the Democratic electorate — though they’re not a significant factor until South Carolina votes on January 29. To win the nomination, Obama will probably need to carry at least two-thirds of the black vote everywhere he runs.

Though the press has been loathe to raise the issue, what no one knows — and what will be very difficult to measure — is whether, sad to say, a white backlash develops against Obama among Democratic voters. If one does, it will probably appear in the form of a slight drop-off in Obama’s pre-election poll numbers in various states. Of course, few voters will tell pollsters that they backed away from Obama because of his race. Instead, it will likely take the form — if it occurs — of voters saying Oprah turned them off, or they found Obama too inexperienced, or even divisive. Of course, those things may be true, too, which is why this issue is one of the election’s great imponderables.

3) Who dominates the electorate: the upper middle class or the lower middle class?
The polls so far indicate that poorer voters tend to favor Clinton, except in the black community, while the affluent tend to favor Obama. That’s good news for Obama in some states, since poorer voters usually don’t vote in as great numbers as the affluent. In New Hampshire in 2004, according to a CNN exit poll, those with incomes of more than $75,000 comprised 35 percent of the Democratic primary electorate — an extremely high total. Put another way, in the last presidential primary, college grads were 56 percent of the total New Hampshire Democratic vote.

If those percentages stay the same in 2008, Obama is in decent shape, especially since Hillary faces competition from Edwards for lower-income voters. Hillary needs to expand the electorate to include more of these voters, particularly in the early primaries — which is why a heavy turnout may be a good sign for her.

4) Is there an unexpected youth vote?
All along, the Obama campaign has been targeting youth. Historically, that’s been a bad strategy, since the young, no matter how many rallies they attend, tend not to vote in as nearly as great numbers as older voters. In the 2004 New Hampshire Democratic primary, for example, voters 18–29 comprised only 14 percent of the electorate, roughly matching those 65 and older (11 percent).

Obama probably needs to increase that ratio — though if he does, it will mean turnout increases. That’s why an upsurge in turnout could be good for either Clinton or Obama — it depends on what’s behind it.

5) As the lesser-known candidates stumble, where do their votes go?
Another great imponderable in the Democratic race is where the supporters of lesser-known aspirants will wind up as their candidates withdraw or stumble. It could go either way: there may be a trend that sees these voters, having rejected Hillary once, rejecting her again, or, taking the opposite course, embracing her (or Edwards) as the “safer,” more experienced candidates in the race. There won’t be a lot of these voters, but, in a close contest, they could make a difference.