It's fun to think about a President Joe Biden, mostly because the guy is lovable. In the relatively low-risk job of vice president, he's a natural — he punches guys' arms and squeezes matronly women and high-fives little kids. Entertainment value aside, though, he will never, ever be president. Indeed, Joe Biden would be ill-advised to run.

A story in The New York Times today explores the emerging 2016 Democratic primary dynamic. It's unavoidable: The presidency is the most interesting aspect of American politics, and speculation about who will run and how they'll do and what it will mean is tough to resist. Put Hillary Clinton and Joe Biden in a room together? You got yet another story.

Mr. Biden faces a situation unique in the annals of modern American politics. He is the vice president, the highest-ranking member of his party interested in running for president, yet he is not the heir apparent. While every sitting vice president who sought it in the last half-century captured his party’s nomination, Mr. Biden would start as the underdog if he ran against Mrs. Clinton, the former secretary of state.

“It’s no secret that he’s thinking about this,” his son Beau, the attorney general of Delaware, said in an interview. “I’m glad he’s thinking about this. But he hasn’t made up his mind.”

A little later, The Times's Peter Baker notes that "it is not clear that a presidential campaign makes sense for Mr. Biden," given how old he is. That may be the least of his problems.

He polls poorly.

The first big poll on the Democratic primaries in 2016 came three days into Barack Obama's second term. (Why the wait?) It and two subsequent polls show that Biden faces tough competition in Hillary Clinton.

January 23, 2013, Langer Research

There is no demographic with which Biden does better than Clinton. In most, he does substantially worse. This is not a head-to-head poll, mind you, but a measurement of favorability — a useful-but-hardly-perfect guide to determine which candidate would be likely to prevail in an election.

Even more useful is this graph, which outlines how strongly people feel about the candidates. Over one-third of voters — of all political persuasions — feel strongly favorable about Hillary Clinton. Just over a fifth feel that way about Biden.

March 7, 2013, Quinnipiac

The next two polls match Democrats up against possible Republican contenders. Notice that Rubio line below; it's the only match-up in any of those presented where Biden does better than Clinton. How the nominee will fare against a Republican challenger is, of course, a key consideration for primary voters.

April 2, 2013, Marist

Marist added in New York governor Andrew Cuomo. Which is good for Biden, since he does better against Cuomo than he does against Clinton in these match-ups. (Cuomo and Rubio polled even, so that value shows as zero.)

2016 is a long time away.

But those polls exclude a full field of Democratic candidates. It's impossible to know at this point who will run or how they'll fare or who might rise to political prominence between now and then. In August 2005 — the equivalent of this upcoming August in relation to 2016 — the Democratic front-runner for the 2008 nomination was Hillary Clinton. The following four candidates, in order: John Kerry, John Edwards, Joe Biden, Wesley Clark. Gallup didn't ask about Barack Obama.

Even if Biden doesn't poll well in head-to-head match-ups against Hillary Clinton, and even if Clinton doesn't run (the only scenario in which Biden might, some think) — it's impossible to know who we would be running against in 2016 or how his tenure as vice president will be perceived at that point. It's very possible that we're now at Peak Biden — and that he has nowhere to go but down.

He has already run against Clinton and lost. Badly.

Joe Biden has run for president before. In 2008, he competed against both Clinton and Obama, and lost. He dropped out after the first contest, in fact, the Iowa caucus, in which he finished fifth. He got fewer than one percent of the votes in a heated three-way contest between Clinton, Edwards, and Obama. But even given that dynamic, he was still beaten by Bill Richardson.

Nor was he a strong fundraiser. Biden was sixth in raising money in 2008, pulling in a little over $4 million. Granted, he was an unknown senator from Delaware at the time, but it's certainly not cause for confidence.

People like Joe Biden because he isn't president.

This may be the strongest reason Biden won't win, by far. When Biden was running in the Democratic primaries in 2007, he was best known for referring to Barack Obama as "the first mainstream African-American who is articulate and bright and clean and a nice-looking guy." This was treated with the cringes one might expect — because Biden was running for president. As vice president, he says goofy (although not overtly offensive) things, and people shrug. That Biden!, they say. The Onion turns him into a goofy character and Biden embraces it. None of this will help if Biden were to decide to run, seriously and without Hillary in the picture, for the highest office in the land.

Bear in mind, there has been a recent example of a gaffe-prone, goofy vice president running for the presidency. In 1999, Dan Quayle decided that he would run for president. He didn't even make it to the first primary.