As of January 15, 2008, Democrats have had two major state contests with two winners, and Republicans have had three major contests with three different winners. Though a few candidates have dropped out, no one has accumulated sustained momentum, let alone obtained a position as the inevitable nominee. Each party has had one opportunity to confer sustained and perhaps unbreakable momentum on a candidate—Democrats for Barack Obama in New Hampshire, Republicans for John McCain in Michigan—but both have declined. Instead, the parties have opted for longer, more drawn-out fights. Why?

It is, simply put, more difficult than usual for voters in either party to make a decision.

The complexities of voter choice in presidential nomination contests can largely be reduced to three factors: ideology of the candidates, personal characteristics of the candidates, and electability—that is to say, how ideology and characteristics are likely to interact with national circumstances and with the identity of the opposing candidate. To a degree that is highly unusual in recent years, the background of the 2008 nomination races has made a jumble of these calculations.

Start with ideology. On the Democratic side, there is no apparent gulf in terms of philosophy or specific policy prescriptions between the major contenders. Hillary Clinton proposes a $70 billion economic stimulus package, Barack Obama $75 billion, with, to be sure, some different emphases but little clear delineation between them. There is little dissension on Iraq among the major candidates, or between the candidates and the MoveOn.org line. Dennis Kucinich is not losing because he is out of the current Democratic mainstream, he is losing because he is superfluous. There is no Henry Jackson, no Joe Lieberman, and no Bill Clinton to challenge the far left of the party.

On the Republican side, there is less uniformity. Instead, there is just confusion. There are a number of candidates who appeal to the conservative base of the party 80 percent of the way; it is just a different 80 percent for each candidate. Giuliani loses pro-life voters; Huckabee loses economic free-marketeers; McCain loses immigration skeptics and, more generally, those who value predictability; Romney and Thompson have checked off all the boxes but have not excited, in Romney’s case because his long-term commitment to social conservatism is suspect. Thus, while ideology is in play, there is no clear-cut confrontation, no Goldwater versus Rockefeller.

Personal characteristics have only offered more confusion for voters. Both parties must face the resurgent importance of the choice between outsiders and insiders. Furthermore, both parties are having difficulty sorting out which candidates fit in which categories. Democrats clearly have an outsider in Barack Obama, but is Hillary Clinton an insider, as the candidate of experience, whose victory would constitute a reprise of the 1990s? Or is she, as some feminists have suggested, an outsider because she is a woman? The Obama-Clinton choice has clearly left many Democrats conflicted in another way, as two official Victim Groups square off against each other and only one can win. In the mindset of the left, cultivated for many years, if you deny the woman you are, ipso facto, a sexist. If you deny the black man you are a racist.

In one sense, the entire Republican field consists of outsiders: two former governors, a former mayor, a long-retired Senator who seems immune to the disease of obsession with the presidency, and a current Senator with a reputation as a maverick. This fact has not kept Republicans from questioning each other’s credentials as outsiders, as when Romney recently attacked McCain for being a Washington fixture. From the other direction, McCain and Thompson are able to argue that they represent a safe outsiderism—that is, an outsiderism that still possesses solid foreign policy experience—in contrast to a Huckabee or a Romney. Even many Republicans want change, and moreso Republican-leaning independents, but, like Democrats, they have not yet decided how much to value change versus experience. In this sense, 2008 is not 1992, when the end of the Cold War freed voters to embrace outsiderism unambiguously.

Finally, calculations by voters regarding the electability of candidates is much harder in 2008 than in other recent elections. As the first race since 1952 in which there is no president or vice-president running, both parties’ nominations are wide open. As analysts have noted, this means that voters who care about electability are trying to hit a moving target. One week Clinton is up, the next week Obama, the week after Clinton. One week Huckabee is up, then McCain, then Romney. Needless to say, candidates match up differently against different opponents, but neither side yet knows who its opponent will be.

At the same time, the extraordinarily early beginning of the nomination voting throws another kind of wrench into voter calculations about electability. The longer it is until the general election, the more difficult it is to predict what the circumstances will be at the time the nation votes. Just as candidates match up differently against different adversaries, they also match up differently against different circumstances. A victory for McCain will be a Republican gamble that the Iraq surge is still working in November and, more generally, that foreign policy is a major concern; a victory for Huckabee or Romney will represent a gamble that economic concerns will trump security by November; a victory for Obama would likewise represent a Democratic bet that foreign affairs will play a secondary role in the general election. Any of those assumptions could easily be upset in the intervening months.

Altogether, voters in both parties are facing a particularly challenging environment in 2008. In some respects, these challenges are a product of the shortcomings of each party’s field of contenders. In other respects, the reasons are structural. In any case, voters of both parties might thank Iowa, New Hampshire, and Michigan for insisting that the games go on. It is still unlikely that the race in either party will go all the way to the national convention, but at least the voters of some later voting states will have a chance to have second or third thoughts before casting their ballots in a meaningful contest.

Andrew E. Busch is a Professor of Government at Claremont McKenna College and an Adjunct Fellow of the Ashbrook Center.