That assumption was always iffy. That electability and support go hand-in-hand means that as support for a candidate drops, so does the perception that the candidate can win the general election. The correlation between the two, in other words, means electability is often just a trailing indicator of primary support anyway.
For former vice president Joe Biden, this was always a looming iceberg. If voters stopped thinking he was the best candidate to beat Trump next year — which they consistently seemed to think — what would happen to his support? Or, conversely (and probably more accurately): If voters stopped supporting him, what would happen to perceptions of his electability?
We’re starting to get an answer to the second question.
On Monday, Quinnipiac University released a poll showing that Sen. Elizabeth Warren (D-Mass.) had taken a within-the-margin-of-error lead over Biden in national polling. In August, she trailed by 11 points. Now she leads by three.
Comparing the new results to August is more broadly instructive. At that point, Biden had an 11-point lead in support (shown on the vertical axis below) but a 37-point lead on the electability question (left to right). (Quinnipiac asks which candidate “has the best chance” of beating Trump.)
The lines show movement over time: When Biden stumbled badly against Sen. Kamala D. Harris (Calif.) in the first Democratic primary debate, his support and sense of electability fell, too, with Harris seeing quick gains on both points. Those gains for Harris have since evaporated.
Notice the diagonal dashed line. Biden had more support on electability in August (49 percent) than overall (32 percent), so his dot is below the diagonal line. Harris at that point was the first pick of 7 percent of Democrats and seen as the most electable by 6 percent, so she was right on the diagonal.
Here’s the shift that happened in the new poll.
Warren had big gains in electability and support. Harris saw both decline.
The other two lines, though, don’t show a link between the two. Sen. Bernie Sanders (I-Vt.) continued to hold steady on the level of support he sees — but the extent to which he’s seen as electable continues to erode. Biden, meanwhile, has seen his overall support sink — but he has also maintained about the same level of electability.
Overall, Warren’s line looks the way you’d expect based on what we’ve seen in the past: up and to the right, gaining support and a sense of electability at the same time. Biden is hanging in there, though, still viewed as having the best chance against Trump by twice as many respondents in Quinnipiac’s poll.
This is national polling, not state polling, so it’s not particularly predictive. But the implication is that the dominant existing calculus — Biden is most electable and, therefore, has the best shot — isn’t as solid as might have been expected.
But, then, we shouldn’t have expected those two things to be as tightly linked as they’ve been presented. We said this in July and will say it again: Biden’s 2020 may look more like Hillary Clinton’s 2008 than her 2016.