I have two words of caution for Vice President Joe Biden as he considers making a third run for the presidency.  I'll get to them shortly.

It can be intoxicating to see the polls and pundits saying more people would vote for him than Hillary Clinton or anyone else on the Democratic side, especially after his dismal previous attempts in 1988 and 2008, but the Veep should be wary about such early indicators.

So far all the conversation has been about personality and style and Clinton's problems plus a generous helping of sympathy for a father who just buried a child for the second time in his life.

Clinton's poll numbers are being driven down largely by the most common of political afflictions – self-inflicted wounds. 

Nearly all the coverage of Biden's presidential musings has been encouraging and sympathetic.  Many Democrats are worried that Clinton will crash and burn, that Vermont Sen. Bernie Sanders, who is closing in on her, is too old and too liberal, and that there are few other viable alternatives. 

Republican have been holding their fire in the hope Biden's entry could spark a destructive battle that will divide and weaken the Democrats.  After all, that's what the GOP is doing to itself, and no doubt there's great hope in GOP circles that Democrats will follow suit, especially if Biden challenges Clinton. Meanwhile, they've been accumulating material to use against Biden, not only his well-known gaffes but also a 40-plus year legislative and political record that can be sliced, diced and interpreted in infinite ways.

On domestic issues he's in synch with the broad majority of American Jewish voters. He's a solid liberal with an appealing record for Jewish voters on both Israel and domestic issues.

He has high name recognition and working class roots.  He has a sincerity, openness and warmth that many find lacking in Clinton.   If it is authenticity that voters are looking for, as the pundits claim, Joe's your candidate.  But he is also undisciplined, and that frequently gets him into trouble.

As of press time, we don't know whether he'll decide to run.  But as he looks at it, I have two words for him to ponder:  Ted Kennedy.

At this point, a year before the convention and 15 months before the election, in August 1979, polls showed Senator Kennedy easily taking the Democratic nomination from President Jimmy Carter.  Gallup had him beating the incumbent two-to-one. 

A few days before his planned official announcement, CBS's Roger Mudd asked the senator why he wanted to be president.  It was a softball question that nearly 20 years earlier his brother Jack knocked out of the park with a simple answer, "That's where the power is."

But Ted was "incoherent and repetitive" and "vague, unprepared," noted Wikipedia.  It was downhill from there.

Kennedy's candidacy quickly did a U-turn as the media and opponents went from discussing Carter's weaknesses to dissecting Kennedy's long Senate record, and as Republican flacks began reminding voters of past Kennedy controversies. There was a reservoir of sympathy for his family's losses but it took more than that to mount a presidential campaign.

It's not just Ted Kennedy.  In more recent elections there were many wannabes who looked promising in the polls and collapsed once they got to the starting line:  Rick Perry is the latest and Rick Walker appears ready to join him  on a list  includes Rudy Giuliani, Tim Pawlenty, Michele Bachmann, John Huntsman, Fred Thompson and Wesley Clark plus some other forgotten hopefuls.

We've heard that Biden's dying son, Beau, had urged his dad to run for president, and that no doubt weighs heavily on him, but it is not a foundation on which to build a national campaign. Even foes praise the dignity with he carries his grief for his son, and he has much public sympathy and affection, but will that be enough to take him to the White House, or even the nomination?

Clinton already has an extensive campaign organization, established operations in key states, the backing of many leading Democrats and a major lead in fundraising that would be tough to match.

I'm not saying run, Joe, run, or don't run.  Just make a hardheaded decision and not an emotional one, and don't be misled by these early polls that reflect name recognition, sympathy, affection and frustration with the front-runner.