In private, some top Democrats remain nervous about the presidential race, despite Joe Biden's lead in swing state after swing state — and strength in states that had looked out of reach (including Georgia, Ohio and Iowa).

Why it matters: The ghost of 2016, when most "experts" looked foolish, haunts Democrats, who see a big win in their data, but fear being blindsided again.

Tom Edsall, who works the political science beat for New York Times Opinion, is up with a smart piece, "Biden Is Not Out of the Woods."

• The most interesting data was a massive surge in registration for working-class whites.
• Edsall quotes a Democratic strategist's privately circulated newsletter as reporting that white, non-college, over-30 registrations in battleground states had recently "increased by 10 points compared to September 2016, and the Democratic margin dropped 10 points to just six points."

Another key point: Pew Research Center polling shows what Edsall calls "a modest drop in the Democratic margin of support among Hispanic Catholics" and "modestly weakened support among Black women."

• And, of course, operatives worry about hazards in properly returning mail-in ballots.

🐦 The bottom line ... Biden campaign manager Jen O'Malley Dillon tweeted last night: "[T]here is still a long way to go in this campaign, and we think this race is far closer than folks on this website think. Like a lot closer."