A quartet of political scientists, writing for the Sunday New York Times, took a relatively novel path to explore not only how Donald Trump won the 2016 election, but also what Democrats might do to get a different result in 2020.

Their approach was to focus deeply on those who voted for Barack Obama in 2012 but didn’t vote for Hillary Clinton in 2016. That includes not only those who voted for Donald Trump, but those who voted for minor party candidates and, most especially, those who voted for Obama in 2012 but didn’t vote at all in 2016. The piece was titled: “The missing Obama millions.”

In fact, of those who voted for Obama in 2012 and didn’t vote for Clinton in 2016, slightly less than half (6 million) voted for Trump. Slightly more than half either voted for a minor party ticket (2.3 million) or (4 million) didn’t vote at all.

The analysis by the foursome (political scientists Jesse H. Rhodes and Brian F. Schaffner of the University of Massachusetts, Bernard L. Fraga of Indiana University and Sean McElwee of Data for Progress) focused a bit on the issue positions of those who left the Obama coalition, but also on the demographics, and they found that a huge majority (84 percent) of those 6 million who switched from Obama in 2012 to Trump in 2016 were white.

But about half of those who switched from voting for Obama to not voting at all were non-white, and most of those were black.

On one level, that’s not too surprising — given the historic nature of Obama’s candidacy, especially for African-American voters, and given the usual fact that whites have a higher turnout rate than blacks — that a lot of black voters turned out for Obama then didn’t vote in 2016.

But the authors went a step further. They suggest that most of the whites who defected from the Obama coalition to the Trump coalition are going to be hard for Democrats to get back. But those who voted for Obama, then stayed home in 2016, will probably vote for Democrats if they can be motivated to vote at all. They wrote:

Democratic strategists should recognize that Obama-to-Trump voters do not represent the future of their party. Obama-to-Trump voters diverge from the Democratic Party on many core issues, and in any case they are not particularly loyal Democrats: Less than one third of Obama-to-Trump voters supported Democrats down-ballot in 2016, and only 37 percent identify as Democrats.

In stark contrast, Obama-to-nonvoters share the progressive policy priorities of Democrats, and they strongly identify with the Democratic Party. Four out of every five Obama-to-nonvoters identify as Democrats, and 83 percent reported they would have voted for a Democrat down-ballot. A similar share of Obama-to-nonvoters said that they would have voted for Mrs. Clinton had they turned out to vote. In short, while reclaiming some Obama-to-Trump voters would be a big help to Democratic prospects, re-energizing 2012 Obama voters who stayed home is a more plausible path for the party going forward.