In the waning time before the last Democratic presidential primaries, Sanders has hitched his hopes on the superdelegates overturning pledged delegates and giving him the nomination.
A key part of his case hinges on general election polls, with the claim that they show he would be the stronger nominee against Trump.
While there are many reasons why superdelegates are quite unlikely to do this, starting with them not reversing the decision of most primary voters and caucus goers for the first time, there are five specific reasons why polls won't help Sanders shift superdelegates.
First of all, national polls suggest Clinton can beat Trump.
After Trump clinched his nomination, the poll gap stayed roughly the same and then, as Trump consolidated Republicans, narrowed. During that time, while a few polls had Trump ahead of Clinton, most did not and the poll averages showed Clinton was a smaller lead.
More recently, poll averages show an increasing lead for Clinton. At the time of this writing, Clinton has a nearly five point lead over Trump in HuffPost Pollster's polling aggregate, and none of the last ten polls found a Trump lead.
Being able to take this solid lead before the end of the Democratic race is a sign to superdelegates that Clinton certainly can win the general election.
Second, opinion data show Trump has serious demographic and electoral college problems that aren't going away.
As Republicans pointed out in their 2012 election postmortem, their party needed to attract more Latinos in order to win. Romney attracted 27% of the Latino vote at a time when at least 40% was needed.
As a 2015 analysis by Latino Decisions showed, a larger percentage of the Latino vote is now needed nationwide, with higher percentages in key swing states. Trump's anti-Latino rhetoric has already turned off these voters. Polls conducted before Trump's racist remarks about a Latino federal judge overseeing a civil fraud trial in which he is involved found support for Trump ranging from 12% to 28%, not enough to win the presidency.
Moreover, among the overall electorates in swing states, Clinton leads in the poll averages. HuffPost Pollster now has Clinton +7 in Michigan, +3 in Ohio, +3 in Virginia and +5 in Pennsylvania.
Again, as this is all before the end of the nomination contest, superdelegates looking at the polls would not foresee electoral problems looming for Clinton.
Third, superdelegates have reason to believe that Sanders' poll numbers are inflated.
One major argument Sanders has been making is that he is in a better position to beat Trump, but this is based on having gone through a primary period when Clinton ran virtually no negative ads against him.
Moreover, there has been very little discussion about votes and positions that would hurt Sanders with the general electorate, with those concern taxes, the cost of his proposed domestic policies, foreign policy, the "socialism" label, or Sanders' personal life.
As such, superdelegates won't just compare matchups between Trump and Clinton or Sanders.
Fourth, superdelegates are not going to ignore polls about voters who are central to the Democratic coalition.
Both exit polls and pre-election polls show that Hillary Clinton's wins in primaries and caucuses on which her pledged delegate allocations are based relied, most of all, on women and people of color. These are the core of the Democratic party.
Women are more than half of the overall electorate and have supported Democratic presidential candidates in greater numbers than men since 1980. Both they and black and Latino voters (and, increasingly, Asian voters) are fundamental to the Democratic coalition and to Democratic electoral majorities.
Moreover, for about fifty years, the Democratic party has been aligned with the civil rights and women's movements and has supported policies for greater power and resources for women and racial minorities. Changes brought about by the McGovern-Fraser Commission and afterwards required equity in representation within the party's governing bodies, including the Democratic National Convention.
Superdelegates will not overturn a Clinton delegate lead built in large part on the preferences of women and people of color.
Fifth, general election polls show that young people are the most pro-Clinton in general election matchups.
The strongest group for Bernie Sanders are young voters and that's led some to suggest that Clinton would have trouble attracting their support.
However, national polls consistently show that young voters support Clinton over Trump more than any other age group. This is true despite their clear preference for Sanders. For instance, a poll this spring from Harvard's Institute of Politics found that, even though 18-29 year olds prefer Sanders over Clinton and see Sanders favorably and Clinton unfavorably, there was a 36 point lead for Clinton over Trump.
With Sanders' strongest backers reporting they would certainly be in Clinton's camp versus Trump, superdelegates attuned to the polls would not find anything near a compelling reason to pick a candidate who won less than the majority of pledged delegates.