For the better part of the last week, Hillary Clinton’s subpar performance at the most recent Democratic debate has been the subject of intense conversation among the other Democratic candidates, the media, and even Bill. At the same time, polls show a tightening of the Democratic race in Iowa and New Hampshire, where Hillary’s lead has been cut in half in the last month. The question has been raised for the first time in recent months whether Hillary is really such a sure bet to win the Democratic presidential nomination.

Such questions reveal a great deal about the short memories of the American political commentariat. For one thing, it was only relatively recently that the major media crowned her nearly invincible. In the spring, discussion of the Democratic race was filled with observations about Barack Obama’s uncanny fundraising ability and Hillary Clinton’s tin ear, as demonstrated by her unsuccessful attempts to sing the national anthem and to imitate the speaking style of black ministers at a civil rights gathering. The discussion has now only come full circle, with the media noticing, as for the first time, what it was fixated on a mere six months ago. Hillary has weaknesses as well as strengths, and there are one or two other Democrats in the field who are strong enough to threaten her.

In a broader sense, as it goes through its gyrations, the national media is forgetting much that has been learned since 1996 about the highly-front-loaded primary and caucus system. This review argues for Hillary to work hard but to expect to win the nomination battle in the end.

There are two really plausible scenarios for the effect of front-loading on live nomination contests. In some cases, it has long been argued, the leading candidates may be so evenly matched at the outset that front-loading helps tremendously the winner of the earliest battles, such as Iowa. In this scenario, an early win gives an underdog candidate momentum that carries him through the decisive portion of the primary and caucus calendar. In other cases, front-loading helps a clear frontrunner by establishing such a heavy early cost in money and organization that few, if any, serious challengers can emerge. In these cases, the frontrunner can afford to stumble once early, because his or her reserves are sufficient to absorb a blow and come back in the decisive next rounds.

There has so far been only one example of the first scenario actually becoming realized: John Kerry’s Iowa-inspired win in the 2004 Democratic nomination race. Howard Dean led the field at the outset of 2004, but was hardly a dominant frontrunner. (His showing in national polls was typically 15-20 percentage points below Hillary Clinton’s standing for the past several months.) Kerry came from behind in Iowa, and his momentum carried him all the way to the nomination. Neither Dean nor anyone else possessed sufficient national resources to absorb the early blow and recover.

In every other competitive nominating race in the front-loaded era, the second scenario has played out. The field featured a dominant, not merely putative, frontrunner. That frontrunner suffered an early setback, but no challenger possessed the financial or organizational resources to capitalize on the opportunity.

In 1996, Bob Dole suffered when his response to Bill Clinton’s State of the Union address was poorly received. In short order, he lost New Hampshire in an upset to Pat Buchanan. However, when the race went into the next rounds, only Dole had the reserves to fight hard everywhere, and Buchanan crumpled (along with the rest of the field).

In 2000, George W. Bush was likewise the leader of the Republican field by a wide margin. After losing to John McCain in New Hampshire, Bush rebounded. McCain was simply unable to sustain his challenge nationally.

In the same election cycle, Al Gore built a dominant position relative to Bill Bradley. Bradley closed the gap in the fall of 1999 and actually led Gore in New Hampshire polls. Bradley then came within a few percentage points of actually winning the New Hampshire primary. From that point forward, Gore overwhelmed Bradley and put out the fire.

The key question, then, is whether Clinton’s position is more like Howard Dean’s or like Bob Dole’s, George W. Bush’s, and Al Gore’s. It is impossible to know for sure how fragile her national lead is until voting begins and she hits a bump in the road. However, at the moment, it seems likely that she fits better with the latter than with the former; that is to say, her position today looks more like a Dole than a Dean. She is also aided (perhaps) by the fact that there is not one anti-Clinton—not one John McCain or Bill Bradley—but two (Obama and Edwards), who will undoubtedly split the core ABC constituency for at least the first round or two. In this respect, she really is like Dole, who had to fend off Steve Forbes and Lamar Alexander as well as Buchanan, but who benefited from his adversaries’ inability to consolidate their efforts. On the other hand, Edwards and Obama might benefit from being able to take turns pushing Clinton hard. In short, Hillary Clinton is not invincible and should never have been portrayed as invincible, but recent nomination history suggests that it is easier to imagine a scenario in which she loses Iowa but holds on to win the nomination through effective use of superior reserves than it is to imagine her losing Iowa and being completely swept from the field by the resultant momentum of a challenger.

None of this is to say that the road to her nomination will be easy, if indeed she travels it. To the contrary, recent nominating history offers no example of a contested race in which the frontrunner did not face at least one extended moment of severe discomfort. And it is far from saying that her nomination will be tantamount to election. Just ask Bob Dole or Al Gore.

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