To the extent Democratic turnout was weak, it was mainly among black voters. Even there, the scale of Democratic weakness has been exaggerated.

Instead, it’s clear that large numbers of white, working-class voters shifted from the Democrats to Mr. Trump. Over all, almost one in four of President Obama’s 2012 white working-class supporters defected from the Democrats in 2016, either supporting Mr. Trump or voting for a third-party candidate.

This analysis compares official voter files — data not available until months after the election — with The Upshot’s pre-election turnout projections in Florida, Pennsylvania and North Carolina. The turnout patterns evident in these states are representative of broader trends throughout the battleground states and nationwide.

The turnout was slightly and consistently more favorable for Mr. Trump across all three states. But the turnout edge was small; in one of the closest elections in American history, it might not have represented his margin of victory.