Cory Booker is the only Democrat with a data-driven electability argument
It's not a strong case, but that's the point
The Democratic base is supposedly obsessed with electability in the presidential primary. A recent poll showed 60 percent of primary voters think it is more important to nominate a candidate who can beat Trump than one which they agree with on the issues. Which is why it is surprising that New Jersey Sen. Cory Booker's campaign hasn't gotten more traction, since he is the only one with a real data-driven electability argument.
Similarly surprising is that a major thrust of Joe Biden's current campaign is that there is something unique about him, a white male moderate with decades in politics, that makes him uniquely electable. Yet beside the fact that significantly more voters know who he is compared to the other candidates, a deficit that would be quickly rectified in a general election campaign, the past doesn't indicate anything about him in particular that is especially "electable."
In the past 40 years, only two Democrats have won the White House. One, Bill Clinton, was a Southern white male governor, but he managed to win twice with less than 50 percent of the popular vote thanks to the strong performance of an eccentric third-party candidate. The other was Barack Obama, a Northern black male senator who won with clear majorities in part due to large minority turn out.
Over that same time period, among Democrats, one incumbent white male president lost (Carter), two white male vice presidents lost (Mondale, Gore), one white male former governor lost (Dukakis), one white male senator lost (Kerry), and one white female former secretary of state (Clinton) lost. White male candidates have had a terrible track record for Democrats in my lifetime, winning just 29 percent of the time while white male former vice presidents have a record of 0-2. By comparison, black male senators have a 100-percent success rate for Democrats seeking the White House. Booker is the candidate that most closely matches the last successful winner in terms of race, age, gender, and political experience. And a profile closer to President Obama's would seemingly be even more of a strategic advantage every year as the demographics in the country shift.
Looking purely at the historical data, Democratic primary voters should be deeply worried about choosing a white male, but strangely, that is not how voters or basically anyone in the media is viewing the 2020 election.
Do I personally think Booker is the most electable Democratic candidate based on such a limited number of data points and variables? I don't know, but that is the point. The number of modern elections is so small, and the number of potentially important variables in each of those elections were so many, there is no way to look at the data and come away with any conclusion with true confidence. At least Booker is the candidate in the race with the best case based on the "data," albeit a very weak case based on very limited data.
One major element of Biden's electability argument is based on his general election polling, but that is also largely a reflection of many voters not really knowing who the other primary candidates are. For example, the most recent SurveyUSA poll found Biden's performance against Trump was identical to that of Bernie Sanders and Michelle Obama, the two other best known political figures in their poll. The other rationale is that Biden has some unique ability to win blue-collar whites in swing states which seems based on little actual information. Biden hasn't won a single election in one of the 2020 swing states, unlike Colorado Senator Michael Bennet, Montana Governor Steve Bullock, former Colorado Governor John Hickenlooper, Ohio Congressman Tim Ryan, and former Pennsylvania Congressman Joe Sestak. Nor has Biden proven he is better at winning white working-class voters than Hillary Clinton who easily outlasted him in the 2008 Democratic primary.
The general notion that Democrats would somehow benefit from running a governor or a white male or someone with decades of experience in politics just isn't supported by modern presidential election results. Many of these claims are based on weak evidence, echo outdated thinking, or are actively undermined by what limited data we have. These issues can likely be attributed to the age, ideology, and background of many of the top figures in the media and the fact that focus groups made up of the tiny segment of swing voters makes for more compelling TV than committed partisans. But the real story of 2020 is mostly about voters' general satisfaction with the current state of the country and the boring operational steps campaigns are taking to improve turnout by a few percentage points. Anyone who thinks they really understand what makes a candidate the "most electable" is either delusional about their abilities or creating a retroactive argument to justify the candidate they like best.