Over the past week or so, the pundits narrative of the race for the for the Democratic Presidential nomination has revolved around the question of whether Hillary Clinton’s nomination is inevitable. Those who say yes point to her large and growing leads in the national polls and in early primary states such as New Hampshire, Florida, and South Carolina (see summary of weekly poll results).

Those who take the opposite view point to Iowa and Howard Dean’s temporary status as frontrunner in the 2004 campaign.

In Iowa, polls suggest a much tighter race than anywhere else. This, plus the fact that caucus polling is less reliable than primary election polling, means that just about anything could happen when voters finally get to participate in Election 2008.

What all this means is that Clinton is a far more serious frontrunner than Howard Dean. She has more organizational depth, support, and other resources than Dean ever imagined. Also, while Dean had a committed following, he was hardly anybody’s second choice during the run-up to Election 2004. Clinton is more acceptable to those who see other candidates as their top choice.

But, her nomination is not inevitable. Self-inflicted wounds are always a threat to any frontrunner and the Senator from New York proved that point last Friday—by a 2-to-1 margin, voters oppose her proposal to provide a $5,000 savings bond for every child born in the United States. More unforced errors might provide just the break needed by her challengers.

And, of course, there is always Iowa. Supporters of Barack Obama and John Edwards are quick to remember that Howard Dean was the polling frontrunner everywhere until he lost in Iowa. They are right to point out that a loss in Iowa would probably have an immediate impact on Clinton’s polling and prospects in other states.

But, the magnitude of the impact will likely depend on the magnitude of the defeat.

In 2004, Howard Dean didn’t just lose in Iowa, he lost very badly. Kerry won 38% of the vote and John Edwards came in second at 31%. Dean couldn’t even reach half of Kerry’s total and finished a distant third at 18%. If Clinton loses that badly in Iowa 2008, her status as frontrunner would be in serious jeopardy. A more narrow loss in Iowa would be a challenge for Clinton, but not necessarily a challenge that would undo her campaign.

At the other end of the spectrum, a Clinton victory in Iowa would likely end any hopes for Obama or Edwards to wrest the nomination from her. As noted last week, Iowa has become a must-win state for the challengers.

In some ways, Clinton’s current status as a frontrunner more clearly resembles that of George W. Bush in Election 2000 rather than Howard Dean in 2004. Bush was related to the last President elected from his political party and had a relatively short career in elected politics. But, he enjoyed strong support from the party establishment and great fundraising capabilities. Bush won the Iowa caucus but was defeated by John McCain in New Hampshire. Still, he had the resources to eventually fight back that challenge to win both the nomination and the White House.

Clinton’s campaign for the nomination also has similarities to Walter Mondale in 1984. Mondale ran as a quasi-incumbent who was challenged by a young charismatic Senator named Gary Hart. While the battle for the nomination may be similar to 1984, the national environment is far more favorable for Democrats than it was when Reagan won 49 states on his way to re-election.

History provides interesting guidelines, but every campaign develops its own story and character. At this point in Election 2008, the political class has been fully engaged in the campaign for a year. But, the voters are just starting to tune in. The impact of the Internet will be felt more profoundly than in any prior election and this year features the first time both parties have had a truly open race for the nomination in more than half-a-century. How those factors will play out remains to be seen.

For now, we simply note that Clinton is a serious frontrunner but her victory is not inevitable.

Rasmussen Reports conducts national telephone surveys on the Presidential race every night and releases updated data from our Presidential Tracking Poll by noon each day, Monday through Friday.

For the seven days ending September 30, 2007, Hillary Clinton earns 42% of the vote. Barack Obama is second at 22% followed by John Edwards at 14%. Bill Richardson and Dennis Kucinich each attract support from 3% while Joe Biden is at 2%. Chris Dodd is supported by 1% Mike Gravel less than half a percent. Thirteen percent (13%) of Likely Democratic Primary Voters are undecided (review history of weekly results).

The seven day results typically include interviews with more than 1,000 Likely Democratic Primary Voters. This includes both Democrats and those independents likely to vote in a Democratic Primary. In some state primaries, independent voters are allowed to participate in party primaries while in others they are excluded. The margin of sampling error for the weekly update is +/- 3 percentage points with a 95% level of confidence.

Updates prior to July 16 were based upon four days of polling conducted the Monday through Thursday preceding release.

Rasmussen Reports continuously updates general election match-ups and other measures for all Republican and Democratic Presidential candidates.