Candidates with famous names have a built-in advantage at the outset of any race, but their name often turns into a liability as the contest unfolds.
We are seeing this with the latest Pew poll showing Jeb garnering a tiny 4 percent. Hillary, despite her "brand," sees her own numbers dwindling in the face of Bernie Sanders populist onslaught.
At the start, a famous name comes with a built-in reputation, donor base, and public recognition.
But, as the candidacy matures, voters recognize the ways in which the current candidate falls short of his namesake.
Jeb is criticized for not having his brother George's energy (Trump says Jeb has "low energy"), wit, or even his speech-making ability.
Hillary gets knocked for not being the natural politician that Bill is and for lacking his political instincts.
While other candidates are free to make their own images, those blessed with famous names must do so in the shadow of their forebears.
But Jeb's problems run deeper than simply those of the generic famous-last-name politician.
They start with the fundamental lack of popularity of his ancestors. After all, Bush-41 was defeated for re-election, primarily because he couldn't hold his base that defected to Ross Perot.
Bush-43 left office under the twin clouds of Iraq and the 2008 economic crash. He had a 34% approval on his departure.
Today, Jeb is running at a turning point in Republican thinking.
The enthusiasm that impelled victories in 2010 and 2014 has morphed into cynicism as Boehner and McConnell have failed utterly to leave a Republican imprint on Washington events.
Out maneuvered at every turn by Obama, they have given the centrist, establishment GOP a negative image among Party voters.
For many, Jeb Bush is the embodiment of that image. His brother, George W. Bush will always be the man who appointed Justice Roberts and sealed the success of Obamacare with his opinion in its favor.
Meanwhile, Jeb has failed to keep pace with his Party's drift to the right. On the twin issues of immigration and education, he has stuck to a centrist position that his Party's base opposes.
Immigration is not just any issue. It is the fundamental key to the maintenance of the United States as we have known it.
There are 7 billion people in the world. Many want to come here. We have learned from bitter experience that amnesty for those who are already here just encourages more to come. But Jeb has learned no such lesson.
And, on education -- the quintessential function of the individual states -- Jeb's embrace of a federally-mandated Common Core flies in the face of the Republican base's increasing reverence for the 10th Amendment.
Finally, Jeb Bush lacks charisma, he is mediocrity submerged in a field of interesting, charismatic and attractive candidates.
Say what you will about Trump, Carson, Carly, Rubio, Cruz, Huckabee, Kasich, Christie or even Rand, they are stand-out personalities with compelling positions and features.
By comparison, Jeb just blends into the background, looking like a less-interesting hybrid of his father and brother.
Bush and his well-heeled backers on Wall Street had hoped to compensate for his shortcomings by amassing a pile of money and an avalanche of endorsements - creating an "air of inevitability."
So far, the big endorsements haven't materialized.
The money did -- more than $120 million. But money has a very limited use in a presidential primary race. It can be very effective in negative advertising aimed at a particular opponent who may not have the cash on hand to reply. But in a sixteen way field, how do you base a campaign on negatives?
To avoid being brushed aside in the whittling down process, a candidate must stand out for his positives.
So far Jeb has not articulated those well, leaving his strongest supporters to wonder whether he could really handle a national campaign against Hillary or another Democrat.
With 24/7 news coverage and three hour debates every few weeks, voters are not going to look to ads, no matter how brilliantly they are produced, to learn about the candidate.
It's a case of voters saying "will I look at the candidate's ad or the evidence of my own eyes?"
For all these reasons and more, Jeb deserves his current 4 percent vote share in the latest Pew Research poll.
He is not a winner.