I don't think people pay enough attention to how possible it is that the 2016 divergence could occur again in 2020. The States of Change report from last year (Demographic Shifts and the Future of the Trump Coalition) pointed this out in some detail. Nate Cohn expands on this idea in a lengthy, data-rich article in the Times. Perhaps most intriguingly, he finds that this unpleasant scenario for the Democrats might actually be more likely in a high turnout election, typically viewed as a big thumb on the scales for the Democrats.
Here's Cohn's case:
"President Trump’s approval ratings are under water in national polls. His position for re-election, on the other hand, might not be quite so bleak.
His advantage in the Electoral College, relative to the national popular vote, may be even larger than it was in 2016, according to an Upshot analysis of election results and polling data....
For now, the mostly white working-class Rust Belt states, decisive in the 2016 election, remain at the center of the electoral map, based on our estimates. The Democrats have few obviously promising alternative paths to win without these battleground states. The president’s approval ratings remain higher in the Sun Belt battlegrounds than in the Rust Belt, despite Democratic hopes of a breakthrough....
Alone, the president’s relative advantage in the Electoral College does not necessarily make him a favorite to win. His approval rating is well beneath 50 percent in states worth more than 270 electoral votes, including in the Northern battleground states that decided the 2016 election.....
But Mr. Trump’s approval rating has been stable even after seemingly big missteps. And if it improves by a modest amount — not unusual for incumbents with a strong economy — he could have a distinct chance to win re-election while losing the popular vote by more than he did in 2016, when he lost it by 2.1 percentage points.
The president’s relative advantage in the Electoral College could grow even further in a high-turnout election, which could pad Democratic margins nationwide while doing little to help them in the Northern battleground states.
It is even possible that Mr. Trump could win while losing the national vote by as much as five percentage points."
Five points! Yup, it could happen.
But what about higher turnout you say. Wouldn't that solve the problem? Maybe....but then again, maybe not. Here's the deal:
"Many assume that the huge turnout expected in 2020 will benefit Democrats, but it’s not so straightforward. It could conceivably work to the advantage of either party, and either way, higher turnout could widen the gap between the Electoral College and the popular vote.
That’s because the major Democratic opportunity — to mobilize nonwhite and young voters on the periphery of politics — would disproportionately help Democrats in diverse, often noncompetitive states.
The major Republican opportunity — to mobilize less educated white voters, particularly those who voted in 2016 but sat out 2018 — would disproportionately help them in white, working-class areas overrepresented in the Northern battleground states...
In recent months, analysts have speculated about a 70 percent turnout among eligible voters, up from 60 percent in 2016.
In this kind of high-turnout presidential election, by our estimates, the tipping-point state would drift to the right as people who voted in 2016 but not in 2018 return to the electorate and nudge states like Pennsylvania and Wisconsin toward the president. At the same time, the Sun Belt would drift left. Arizona could overtake Wisconsin as the tipping-point state. But even in this hypothetical high-turnout election, the president’s approval rating in Arizona would be higher than it was in 2018 in Wisconsin. It becomes harder for the Democrats to win the presidency....
Democrats could nominate a candidate who tries to win the presidency by mobilizing a new, diverse coalition with relative strength in Sun Belt states, while making little or no effort to secure the support of the white working-class voters with reservations about the president.
The Democrats could certainly win in the Sun Belt states, even in Texas. Perhaps this kind of Democrat could generate such a favorable turnout that it helps the party even in relatively white states.
But it’s also a strategy that would tend to increase the risk of a wide gap between the Electoral College and the national vote. It’s also hard to see how it would be the easier way forward for Democrats, at least as long as the president’s approval rating in the Rust Belt remains so much lower than in the Sun Belt states."
There's a lot more in the article, including detailed state by state approval ratings and a very interesting discussion of Trump's standing in Wisconsin overall and in the Milwaukee metro area in particular.eas
But would you like a very short summary of what all these data are saying? Here it is: fight like hell for the Rustbelt--especially Michigan, Pennsylvania and Wisconsin--or risk a second term for President Trump even as the Democratic candidate easily carries the popular vote.