The Washington PostDemocracy Dies in Darkness

How likely are Bernie Sanders supporters to actually vote for Donald Trump? Here are some clues.

Bernie Sanders and Hillary Clinton make nice at a Democratic presidential debate. (Wilfredo Lee/AP)

The answers to three questions will tell us nearly everything we need to know about who will win the White House in November.

  1. Will the Republican Party unify behind its nominee?
  2. Will Democrats unify behind theirs?
  3. Will white voters make up a larger percentage of the electorate in 2016 than in recent elections — and will they be lured further to the right by Donald Trump?

There's overlap between those questions, of course. There are a bunch of white voters who need to be part of the groups unifying behind each candidate, for example. But if we knew conclusively what the answers to those questions would be, we could skip the next six months of the election.

In the past two presidential-election cycles, the answer to the first two questions has been yes. But in case you hadn't noticed, 2016 is not exactly like 2008 and 2012, in a wide variety of ways. With new Washington Post-ABC News polling in hand, we can try to answer that second question, the most interesting at the moment: Will Democrats come home?

The question, rephrased, is whether Sen. Bernie Sanders's enthusiastic base of support will line up behind Hillary Clinton when the Democratic contest is settled once and for all. It's a base that heavily sees itself as independent (rather than as members of the Democratic Party) and a group which, in our most recent poll, is not unwilling to consider voting for Donald Trump. Twenty percent of Sanders supporters indicated that they plan to vote for the businessman in November.

It's important to note that this has shifted since our last poll in March. At that point, only 9 percent of Sanders supporters said they planned to vote for Trump.

For the most part, supporters of Sanders view Trump about as negatively as supporters of Clinton do. Less than 20 percent see Trump in a favorable light — but they are also much more likely to view Clinton negatively. More than half have a negative opinion of the front-runner.

Which is why more supporters of Sanders who plan to vote for Clinton in November are doing so not because they like Clinton, but because they dislike Trump. Of those who plan to vote for Trump, they're more likely to do so because they dislike Clinton (though we're talking about a small sample of respondents here).

Let's loop in that third question. In both 2008 and 2016, one of the most fervent groups of voters opposing Clinton in Democratic primaries has been white men. This group — particularly white men without college degrees — is one of those groups to which Trump hopes to appeal.

Among Democrats, including supporters of Clinton and Sanders, Trump also does better with white men than he does overall.

White men who voted in the Democratic primaries are more likely to view Trump as qualified to serve as president than Democrats do on the whole.

And just as we found that white working-class voters think that Trump would be stronger than Clinton in addressing the needs of the middle class, white male supporters of Sanders give Clinton only a narrow margin over Trump in that regard.

In 2008, we saw that antagonism from Clinton supporters toward Barack Obama was near its peak in May, as the hard-fought race neared its end. That's probably true here, as well. The percentage of Sanders supporters who say they'll back the Republican in November is lower than the percentage of Clinton supporters who said the same eight years ago. Some of those voters ended up voting for John McCain.

What's different now is that Donald Trump is making an explicit, effective appeal to one of the core groups that opposes Hillary Clinton, white men — and that group is more open than other Democrats to being wooed. The positive sign for Clinton is that there aren't a lot of Sanders supporters right now who plan to vote for Trump because they like Trump. If they can get over their current dislike for Clinton, the answer to Question 2 will be "yes." If not, that answer will apply to Question 3 — and Donald Trump will take another step toward 1600 Pennsylvania Ave.