The biggest hurdle for Hillary Clinton as she contemplates another White House bid in 2016 can be effectively summed up by Timon, the meerkat from "The Lion King": "You've got to put the past behind you."

Former United States Secretary of State Hillary Clinton attends a roundtable discussion held by Univision between parents of elementary school children and politicians regarding language learning and preschool on February 4, 2014 in New York City.  (Photo by Andrew Burton/Getty Images)

Elections are, fundamentally, about the future. The candidate who best captures the hopes of what people want for that future usually wins. It's why Barack Obama is president right now and John McCain and Hillary Clinton, well, aren't. But, for Clinton, putting the past behind her is extremely difficult -- because there is just so much past between her and the American public. No other potential candidate in 2016 (or any other political public figure, for that matter) has spent the better part of the past three decades in the national spotlight the way she has.

"Hillary embodies the last line of "The Great Gatsby": 'So we beat on, boats against the current, borne back ceaselessly into the past,'" said Carter Eskew, a longtime Democratic media consultant. "She'll never put it all behind her. But she has such tremendous strengths right now it may not matter." (Eskew quotes "The Great Gatsby," we quote "The Lion King." Draw your own conclusions.)

The latest example of Clinton's past coming back to her arrives via the Free Beacon, a conservative Web site, that has dug through the papers of Diane Blair, a longtime Clinton friend, to paint an at-times unflattering portrait of the at-the-time First Lady. Like, for example, this from a confidential memo sent by Bill Clinton's pollsters during the 1992 campaign: "What voters find slick in Bill Clinton, they find ruthless in Hillary.”  There's plenty more like that in the Free Beacon piece; nothing that would disqualify Clinton but plenty that reinforces some of the negative caricatures of her that Republicans (and maybe even her Democratic primary opponents such as they will be) will draw if she runs in 2016.

The difficulty in all of this for Clinton is that her past plays no small part in why she looks so strong today as a presidential candidate. First Lady, senator, presidential candidate, Secretary of State. That's how Clinton has spent the last 30 or so years, an unparalleled resume of public service  that, when it's all added up, gives people tremendous confidence in her ability to do the job of president and accounts for her clear leads against all comers in early polling.

And yet, Clinton had much that same advantage -- resume wise -- in the Democratic primary in 2008. And it was turned into an anchor around her neck by Obama and his team. "I know I haven’t spent a lot of time learning the ways of Washington," Obama said in his announcement speech seven years ago today. "But I’ve been there long enough to know that the ways of Washington must change." And, throughout the campaign, he turned Clinton's experience against her -- painting her as a creature of a broken Washington rather than someone uniquely positioned to fix it.

In 2016, there is no Obama-like figure waiting in the Democratic primary -- at least at the moment -- but a number of the potential Republican nominees (Scott Walker, Marco Rubio, Bobby Jindal etc.) are a generation younger than Clinton and have spent far less time in public life. That makes it a certainty that whomever Republicans nominate -- unless it's Jeb Bush -- a central piece of their argument against Clinton will be that she represents the past and they the future.

How does she solve that problem? "The strategic requirement is to create a present story so glorious that any negative factoid of the past evaporates," said Hank Sheinkopf, a Democratic consultant based in New York City.

That is, of course, easier said than done when it comes to Clinton. The past is part of Clinton's present and will necessarily be part of any future bid too. That means that there will be more stories like this one in the Free Beacon that remind people of the things they don't like (and some of the things they do like) about her. The challenge will be to keep them at molehill level while simultaneously trying to find a way to cast her past experience in a forward-looking light in a way she and her campaign never did in 2008.

Clinton's past -- the fact that it exists and how its covered -- is yet another example of how she is unlike any other candidate who is or might run for president in ways both good and bad for her chances.