Every early poll, including the regular monthly polls by Zogby Analytics, suggests that former Secretary of State and First Lady Hillary Rodham Clinton is the shoo-in Democratic nominee for President in 2016. Zogby Poll numbers are a little less sanguine for Mrs. Clinton but still show her 32 points ahead of her nearest rivals nationally. But even now, as I have reported in an earlier Forbes post, she is only polling 45%.

No doubt she will get a big boost from her announcement and her staff promises to raise a stunning amount of money to scare any credible challengers. But she also carries some baggage that could very well dog even the best organized and funded campaigns. Reeling from charges that in 2007-2008 she was wooden, remote, and too “inevitable” to the point of arrogant, the new Hillary promises to be more personal, a new and proud grandmother. But this in itself is reinvention and that is something to hard to accomplish when everyone knows you and is watching your every move. To be fair, Mrs. Clinton showed a warm, personal and genuine side to her when she successfully won her Senate races in New York we have to see if she is a little rusty from being away from the campaign trail so long. I am also not sure Americans love her husband as much when he campaigns for her as much as when he has campaigned for others. In addition, the GOP will be gunning for her, spending record amounts of money on opposition research and some polls are already showing her not only tied or losing in some key states to Senators Rand Paul or Marco Rubio, but only polling in the low 40s – not a great showing for such a well-known and inevitable nominee.

But there is also the question of history as it relates to Democratic presidential primaries. The fact is that more often than not, Democratic voters tend to chew up and spit out their early frontrunners. The following stories are well-known by political junkies but they bear repeating today, the day of the Clinton Announcement.

In 1968, then incumbent President Lyndon B. Johnson actually won the New Hampshire primary (as a write-in, no less) over anti-Vietnam War challenger, Minnesota Senator Eugene McCarthy. But McCarthy performed so much better than pundits’ expectations that he received the “3 M’s” from the first primary – media, money, and momentum. In short order, LBJ announced that he would not seek reelection and New York Senator Robert F. Kennedy entered the race.

In 1972, early bets were on Maine Senator Edmund Muskie who had performed so well as the Vice-Presidential nominee in 1968. He was aided by being from the state right next door to New Hampshire, always an important advantage. To this day there is still debate whether or not Senator Muskie actually wept following a defense of his wife who had been gratuitously attacked — or he was simply brushing aside a snowflake on a winter day. In any event, the press seized on it and Muskie entered a freefall. He, like LBJ in 1968, actually won the primary, but not by enough, beating South Dakota Senator George McGovern by a slimmer margin than expected. McGovern went on to win the nomination.

In 1976, several party heavyweights – among them Washington Senator Henry “Scoop” Jackson, Indiana Senator Birch Bayh, Oklahoma Senator Fred Harris, Arizona Congressman Morris Udall, and Alabama Governor George Wallace. Defense Hawk and domestic liberal Jackson was considered the favorite. None of them matched the warm persona and plodding ground game of former one-term Georgia Governor Jimmy (“Jimmy Who”) Carter, who became the 39th President of the United States.

In 1980, Mr. Carter was the underdog to Massachusetts Senator Edward M. Kennedy, who battled the President Carter down the wire, but was clearly overwhelmed even before the Democrats met in the summer.

Colorado Senator Gary Hart, the architect of Senator McGovern’s nomination, almost defeated runaway favorite, former Vice President and Minnesota Senator Walter Mondale in 1984 and in 1988, Massachusetts Governor beat early frontrunner Missouri Congressman Richard Gephardt for the nomination. 1992 was to be all about New York Governor Mario Cuomo who electrified viewers with a near perfect Keynote Address at the 1984 Democratic National Convention. Arkansas Governor Bill Clinton did not even enter the race until October 1991 and only came in second place in the New Hampshire primary.

Vice President Al Gore was the only inevitable non-incumbent candidate to win the primaries and nomination, but the inevitable 41st President lost the general election. In 2004, Vermont Governor Howard Dean led the Democratic field for nearly all of 2003, but was upended by Massachusetts Senator John Kerry when voters decided (according to Zogby Polls) they preferred a candidate who they felt could truly win the election.

And Mrs. Clinton’s inevitable nomination in 2008 was just not to be.

In short, Democrats have a tradition and it doesn’t necessarily favor the early best-known, best-funded, all-but-assured nominee.