A majority of Democrats want Hillary Clinton to face a primary challenge in 2016, according to new Washington Post-ABC News polling. That number jumps to six in ten liberal Democrats, the group that, at least in theory, has the most sway over deciding the identity of the party's nominee in the next presidential campaign.

Given those numbers, you would think people would be lining up to take on Clinton. But, they're not. Like, at all. Much of that absence has to do with the fact that for all the interest among Democrats to have a real contest for the nomination, those same people overwhelmingly favor Clinton in a hypothetical presidential primary matchup; Clinton leads Vice President Joe Biden 69 percent to 12 percent in that same WaPo-ABC poll. So, Democrats might say they like the idea of a primary challenge to Clinton but when confronted with, well, a primary challenge to Clinton, they seem entirely uninterested in their actual options.

That said, there are plenty of candidates who will look at those Post-ABC numbers and see a path to relevance -- if not victory -- in them. Here's a quick look at the people who might run, why and why they won't seriously challenge her.

Jerry Brown, governor of California

Jerry Brown (Photo by Justin Sullivan/Getty Images)

WHY: He's Jerry Brown! He loves running for president -- he ran in 1976, 1980 and 1992 -- and he's the sitting governor of the largest Democratic state in the country. Plus, there's no love lost between he and the Clintons.  “If no one runs and [everyone] says we’ll have an absent Democratic nominee, would I rule that out?” Brown told WaPo's Phil Rucker when asked about the possibility of a presidential bid in 2016. “I mean, that would be a little silly, wouldn’t it?” Yes, yes it would.

WHY NOT:  In that same interview with Rucker, Brown makes clear that the nomination is Hillary's for the taking. Plus, at age 76 and on the verge of winning another four years to run California, there's no way Brown takes a flyer on such a longshot bid.

Howard Dean, former governor of Vermont

Howard Dean

WHY: Think back a decade when Dean, then a little known governor from New England, soared above the so-called "preferred" candidates of the party thanks to a populist message that perfectly fit the moment. It's been 10 years since Dean's campaign collapsed in Iowa but it's easy to see how he might wonder from time to time about whether he could rekindle some of the magic he found back then. Dean has made trips to Iowa and New Hampshire -- not accidental -- and is giving out cryptic quotes like "you never say never."

WHY NOT: In politics, you never get a second chance to make a first impression. And, the lasting image most Democrats have of Dean is of the "scream" -- not exactly a confidence-inducing moment.

Martin O'Malley, governor of Maryland

In this Sept. 4, 2012, photo, Maryland Gov. Martin O’Malley addresses the Democratic National Convention in Charlotte, N.C. (AP Photo/J. Scott Applewhite)

WHY: O'Malley is term limited out of office at the end of this year and he has long wanted to run for president. In a Hillary-less field, there's an interesting case to be made for O'Malley given the liberal record he has wracked up during his two terms in the Old Line State.  He is also a former campaign operative -- he did advance for then Colorado Sen. Gary Hart's 1984 presidential -- and knows Iowa like the back of his hand.

WHY NOT: O'Malley is simply not in the same orbit as Clinton. (In O'Malley's defense, neither is anyone else in the potential field with the possible exception of Joe Biden.) The Post-ABC poll showed O'Malley getting 1 percent of the vote in a hypothetical Democratic primary matchup.  That's way too big a hill to climb.

Bernie Sanders, Senator from Vermont

Senate Veterans Affairs Committee Chairman Sen. Bernie Sanders, I-Vt., speaks on Capitol Hill in Washington, Thursday, May 15, 2014, during the committee's hearing to examine the state of Veterans Affairs health care. (AP Photo/Cliff Owen)

WHY: Sanders, a self-professed socialist, has been outspoken in his belief that corporate interests and big money players have too much power in politics and that such a viewpoint needs to be represented in the Democratic field in 2016.

WHY NOT: Sanders is more cause than candidate. His goal, if he decided to run, would be to move Clinton to the ideological left on issues that matter to him and other like-minded liberals, not to win.

Brian Schweitzer, former governor of Montana

September 4, 2012 - Senator Mark Begich and Governor Brian Schweitzer at Washington Post Live's Energy & the Election breakfast forum at the Democratic National Convention in Charlotte, North Carolina.

WHY:  No one has been more outspoken than Schweitzer about the negatives of nominating another Clinton. Schweitzer told Time magazine recently that "of course" he'd be a better president than Hillary Clinton, adding: “You can’t be the candidate that shakes down more money on Wall Street than anybody since, I don’t know, Woodrow Wilson, and be the populist."  Give him this: He doesn't lack for self confidence.

WHY NOT: Schweitzer has a schtick -- plain-talking populist -- that likely has a shelf life on the national stage. Plus, he didn't go from a sure-thing candidate for the open seat of Sen. Max Baucus (D) to suddenly taking a pass on that race by accident.