For a lot of candidates, that won’t really matter. When Rep. Tim Ryan (D) dropped out, the almost-zero percentage of the electorate he had secured would have an only slightly more substantial effect than pouring a cup of water into Mosquito Lake. (This is a large lake near where Ryan lives. It is a joke intended for people in or from his district, a group that probably made up the majority of his support in the first place.)
For some candidates and for some moments, it could be critical. It will be important at the Iowa caucuses, for example, when supporters of candidates who didn’t hit a certain threshold will have to choose a new candidate. It will also be important once more-popular candidates leave the race or when multiple candidates leave at once.
So where will those supporters go? To some extent, it depends on where they started.
On Saturday, The Washington Post and ABC News released a poll looking at the state of the Democratic field. Included in that survey was a follow-up question: Who’s your second-favorite candidate? Former vice president Joe Biden and Sen. Elizabeth Warren (Mass.) were the only candidates with enough overall support to break out the second choices of their supporters with any significance.
This is the overall flow of support. The width of arrows corresponds to the percentage of respondents identifying the candidate as their second choice. A dotted line indicates zero support.
For example, consider the interplay between Biden and Warren. About 25 percent of Biden supporters pick Warren as their second choice, while 17 percent of Warren supporters pick Biden. The Biden-to-Warren arrow is wider than the Warren-to-Biden one.
We’ve clumped together supporters of all of the other candidates as another group. Biden and Warren are the second choices of those voters to about the same degree (24 or 23 percent, respectively).
Overall, Sen. Bernie Sanders (Vt.) was the most common second choice of Democrats, with about a fifth of respondents picking him. That’s largely because he’s the second pick of more than 3 in 10 Biden supporters and more than a third of Warren backers. Only 7 percent of those identifying another candidate as their primary preference identified Sanders as their second choice. In part, that’s because about half of those “someone else” Democrats themselves support Sanders as their first pick.
About 6 percent of Biden supporters and the same percentage of those supporting someone besides Warren say they wouldn’t back anyone as their second choice. Only 2 percent of Warren respondents said the same thing.
Sen. Kamala D. Harris (Calif.) and Mayor Pete Buttigieg of South Bend, Ind., were each the preferred second choice of 8 percent of Democrats. They were the combined second choice of 22 percent of Warren supporters, compared with 15 percent of Biden supporters and 14 percent of those picking someone else.
The challenge for potential spoilers here is that so much of the support that flows between candidates goes to other candidates who are already doing well.
Former HUD secretary Julián Castro and businessman Andrew Yang both need to cobble together a lot more support to have a chance, for example. But only 2 percent of respondents overall picked either candidate as their second choice. Six percent of Warren supporters picked Castro as their second choice, somewhat good news for him. But zero percent of Biden supporters chose Yang, significantly worse news for him.
This is a largely academic exercise, because voting will reshape things significantly. But it does offer insight into how voters are considering the candidates. That a third of Warren backers see Sanders as their second choice makes sense — but that 31 percent of Biden supporters do, too, is more surprising.
Of course, being the preferred back-up candidate among Democratic voters is not quite the same as winning the party’s nomination. As Sanders himself can tell you.