Vice President Joe Biden is reportedly nearing a decision about whether to run for president — and if he decides to go for it, he'd seem on paper to make a formidable candidate. Not only is he a sitting vice president, but many commentators say he has charisma and "authenticity" that contrast nicely with the overly scripted, "polarizing" Hillary Clinton. And since the summer, his favorable ratings have dramatically improved, and he's started doing better than Clinton in polls of general election matchups with leading Republicans.

But past indicators of Biden's political appeal — among the Democratic electorate, the party, and the American public more broadly — suggest that he'd face a very difficult road ahead if he runs.

During his 2008 presidential run, Biden performed abysmally, dropping out after getting less than 1 percent in the Iowa caucuses. For most of the time since he's been veep, he has not been particularly well-liked among the public, with more people usually viewing him unfavorably than favorably. And most of the party elites and interest groups that political scientists argue play an important role in the primary process have shown no great desire for a Biden bid, rushing to endorse Hillary Clinton rather than waiting for the veep to make up his mind.

Worst of all for Biden's primary chances, he hasn't been able to top 25 percent support in more than 140 national polls of Democrats that have tested his name.

That's an incredibly weak performance for someone with the advantage of being his party's sitting vice president — so weak that many have long wondered why Biden can't seem to get any respect. Part of this is simply that Democrats prefer Hillary Clinton, the long-familiar 2008 runner-up who'd make history as the first woman president. Biden doesn't seem to have an obvious policy-based case for why liberals should prefer him to Clinton, and his election wouldn't mean a demographic first. And he's culturally out of step with today's Democratic Party.

Beyond that, Biden's very persona has made him difficult to take seriously — his jokey, unscripted, gaffe-prone style makes him a figure of fun. Democrats may have affection for Biden, but few people want to give the nuclear codes to someone they view as America's wacky uncle. So, barring some sudden and scandalous revelation that ends Clinton's career, if Biden does get into the race, there's little reason to expect him to win.

1) Democratic voters don't want Biden

Let's start with the Democratic voters, who have been repeatedly asked for years whether they want Joe Biden to be their nominee and overwhelmingly said no every single time.

Despite his more prestigious job title, Biden is the same person he was when he ran for president in 2007-'08, with the same basic shtick. Back then, he got off the occasional debate zinger, but performed very poorly in the Iowa caucuses, coming in fifth place, far behind Barack Obama, John Edwards, Hillary Clinton, and Bill Richardson. He quit the race that night.

It's also odd that much of the discussion about Joe Biden's potential appeal to Democratic voters seems to ignore the fact that he's been offered as an option to them in over 140 national polls, going back to late 2012. As mentioned above, HuffPost Pollster has tracked them all and found that not only has Clinton led every single one, but she leads Biden by, on average, 30 points. In only two of these polls has Biden come within 20 points of the frontrunner.

Again, this is a dreadful result for someone who has the advantage of being the sitting vice president. It isn't just because Clinton's in the race and Biden isn't — her massive lead existed for years before she started running, and indeed, Biden's numbers are likely benefiting from the more positive media coverage given to a non-candidate. It isn't just because Biden has low name recognition — unlike Bernie Sanders, who surged to second place in polls this year, the vice president is already well-known to the Democratic electorate. He also doesn't have a natural ideological constituency among which to build support.

Furthermore, Biden doesn't have a promising opportunity in any early state — he's polling just as badly in Iowa and New Hampshire as he is nationally. His allies have floated a strategy where Biden will focus on South Carolina, but that's really just an attempt to disguise how grim those Iowa and New Hampshire numbers look.

2) The Democratic Party establishment doesn't want Biden

Political scientists often caution that early polls are frequently wrong, since many voters are unfamiliar with the candidates or aren't paying attention yet. Some prefer to focus instead on the behavior of important players in the party. Are they throwing their support behind one candidate, are they holding back, or are they split?

The answer, for the Democrats, is clear — Clinton is utterly dominating in endorsements, winning far more of them far more quickly than any Democratic nominee in a contested race in the modern primary system. According to FiveThirtyEight's excellent endorsement tracker, Hillary Clinton has already been endorsed by 157 sitting Democratic governors, senators, or US House members. This is all despite the fact that Biden has repeatedly said he is still considering a presidential bid.

Yes, Clinton was the frontrunner and the endorsement leader in 2008, too. But her performance back then actually wasn't so strong, historically. According to the political scientists who wrote The Party Decides, by the time of the Iowa caucuses, her endorsement tally was well behind Al Gore in 2000, Bill Clinton in 1992, Jimmy Carter in 1980, and Walter Mondale in 1984. That showed there was some reticence among major Democrats, which hasn't appeared to be the case this time. Every indication so far is that most top politicians, operatives, and donors want Clinton to be the nominee. Her email scandal might have raised some doubts — but not enough to produce any evident groundswell to Biden.

3) Democratic interest groups and progressive activists don't want Biden

Lurking in a lot of this Biden buzz is the idea that his run would excite progressives. For instance, National Journal's Josh Kraushaar wrote that he could run as "a liberal loyalist for this president who doesn't shade his views with excessive nuance," in comparison to the overly cautious and calculating Clinton.

But if there's unhappiness with Clinton, it's hard to see why the party's major activists or interest groups would view Biden as the solution. He's been a mainstream Democrat for most of his career, and actually has a more conservative record than Clinton on several issues.

For instance, he was the lead author of the 1994 crime law, which is now reviled on the left for lengthening prison terms and worsening America's mass incarceration problem. He championed the interests of the credit card industry in the Senate, and backed a 2005 law making it tougher for people to file for bankruptcy protection. And he's long been a centrist on abortion rights, and voted repeatedly for the Hyde Amendment, which blocks most federal funding for abortion, during his long Senate career. Plus, he supports the administration's Trans-Pacific Partnership deal, which is loathed by some on the left.

The one issue on which Biden has a strong case for being more liberal than Clinton is foreign policy, as Jonathan Allen has written in his book HRC. On several occasions within the Obama administration, the two disagreed, with Biden usually being more cautious about intervention overseas — from his efforts to limit the Afghanistan troop surge to his skepticism about military intervention in Libya to his advice to Obama not to launch the raid that ended up killing Osama bin Laden. However, his record before that would be a tougher sell to progressives — like Clinton, he voted to authorize the Iraq War in 2002.

Regardless, though, foreign policy doesn't seem to be at the forefront of Democrats' concerns this year. Meanwhile, Clinton has already tacked to the left on several issues important to the Democratic base, from criminal justice reform to campaign finance to trade. And some further-left progressives who aren't satisfied with her are already tremendously excited about Bernie Sanders, who represents their views far better than Joe Biden. So from a policy, activist, or interest group perspective, it's difficult to see the rationale for a Biden candidacy.

4) The general public hasn't liked Biden much (except for this summer)

Moving beyond the Democratic primary and on to the general public, Joe Biden's favorability ratings have looked quite good among voters as a whole in the past few months. According to the HuffPost Pollster average, around 49 percent of Americans view Biden favorably, compared with only 37 percent who view him unfavorably. That's far better than Clinton, who is viewed favorably by just 42 percent, and unfavorably by 51 percent.

Yet there are many reasons to believe this is temporary. First of all, the positive views of Biden are a very recent development. Before this summer, Biden's favorability rating was consistently underwater. Since then, he's benefited from sympathetic media coverage following his son's death — and also from the fact that, unlike Clinton, he's not an actual candidate, and so is removed from day-to-day partisan clashes and negative media scrutiny. Remember, before Clinton was actually running, her favorability ratings were much higher (well above Biden's).

If Biden returns to the partisan fray, media coverage will begin to give more attention to his weaknesses, rather than just focusing on the question of whether he'll run. Meanwhile, Democrats supporting other candidates and Republicans will all be reminded of reasons not to like the vice president.

5) The press would love Biden to run

What is the case for Biden over HRC? Youth?❌ Gender?❌ Broad party support?❌ Lefty cred?❌ Money?❌ Superior campaigner?❌ Makes no sense. — Ryan Lizza (@RyanLizza) August 2, 2015

Better liked by the press and more fun to cover ✔ https://t.co/SUhoFtLLVe — Brendan Nyhan (@BrendanNyhan) August 2, 2015

As political scientist Brendan Nyhan suggested on Twitter in August, the main constituency for a Biden 2016 campaign — other than the vice president's own friends, staffers, and family — is the press.

First of all, the press faces natural structural incentives to be more critical of the frontrunner in any long race — it's natural for the person more likely to be president to get more scrutiny, and a closer race makes for a more compelling story. On top of that, there's been longtime tension between top media organizations and Hillary Clinton. Biden, meanwhile, is both better-liked by many reporters and, as Nyhan says, more entertaining to cover due to his unscripted style.

And finally, a Biden challenge to Clinton would make for a particularly exciting story: the battle for Obama's legacy. As politically weak as Biden is, he'd still probably give Clinton a tougher challenge than anyone else in the race. Drama would ensue. Juicy stories would leak out. Traffic would soar. Books would be sold.

But if no tremendously scandalous revelation transforms the race, the story is highly likely to end up the same way — without Biden as the Democratic nominee.