His average deficit against Joe Biden in national polls has ballooned from 6 percentage points in March to 9 points in July. In the latest NBC News/Wall Street Journal poll, published last week, the former vice president leads Trump 51 percent to 40 percent — larger than his 7-point lead in the NBC News/Wall Street Journal poll from June.
But a closer look at the cross-tabs of recent surveys yields some surprising findings: Trump is actually performing a bit better with nonwhites than he did against Hillary Clinton in 2016. And the group fueling Biden's polling surge is seniors and white voters with college degrees.
The 2016 election was defined by mass defections to Trump of the remaining white, working-class members of the Democratic coalition, particularly in heartland states.
Much in the same way, the 2020 election is currently on track to see mass defections of the remaining white professional members of the Republican coalition to Biden — a trend disproportionately playing out in the suburbs, where those voters tend to live.
In an average of nine live-interview national surveys conducted since the start of June, Biden is clobbering Trump 58 percent to 37 percent among whites with college degrees, more than double Clinton's 51 percent to 42 percent lead among that group in 2016, according to the Cooperative Congressional Election Study, a nationally representative sample of 64,600 adults.
Biden has also modestly cut Trump's lead among whites without degrees. Trump now leads Biden 55 percent to 37 percent in that group; in 2016, Trump led Clinton 59 percent to 35 percent among the same group.
Even more dramatically, Biden has reversed Trump's 2016 lead among voters age 65 and older. In 2016, Trump carried seniors 56 percent to 41 percent, according to the CCES data. But Biden, who carried seniors overwhelmingly in the Democratic primaries, leads Trump 50 percent to 45 percent among the oldest voters in the average of current polls.
If there's a surprising weakness for Biden, it's nonwhite voters, especially Latinos. He's carrying African Americans by 75 points over Trump in the latest polls, down from Clinton's 80-point margin in 2016. But Trump has narrowed the gap among Latino voters to 30 points, down from his 40 point deficit four years ago.
Latinos, along with voters 18 to 29 years old, have some of the highest undecided rates in today's polls. Perhaps fortunately for Biden, Latinos are underrepresented in the Electoral College battlegrounds.
In 2016, Latinos made up 9 percent of the nation's voters, but they were less than 4 percent of all voters in all but three of the 10 closest states in 2016: Arizona (17 percent), Florida (17 percent) and Nevada (16 percent). That could limit the real benefit of any Trump improvement with Latinos since 2016.
What's more, Biden's relative weakness with Latinos may be offset by the fact that Arizona and Florida among all the battleground states have the highest shares of seniors, a group with which he is demonstrating surprising strength.
Trump's erosion among college-educated white voters helps explain why Biden is polling so competitively in Texas and Georgia, traditionally GOP states with vast numbers of suburban white professionals who supported Trump in 2016. It also tracks with congressional district-level polling showing Trump's numbers weighing down Republican candidates in traditionally GOP-leaning suburbs near cities like Cincinnati, Indianapolis, St. Louis and Omaha, Nebraska.
A silver lining for Trump has always been that whites without college degrees, by far his best group, are overrepresented in battleground states, especially in Great Lakes states like Michigan, Pennsylvania and Wisconsin. But they are gradually shrinking as a share of the electorate everywhere, as the nation becomes more diverse and college-educated.
Census estimates suggest that in 2020, the number of voting-eligible whites without college degrees could decline 7 percent versus 2016. Meanwhile, the number of voting-eligible, college-educated whites is poised to increase 16 percent and the number of eligible nonwhites is on track to increase 11 percent. In addition, the number of eligible voters 65 and older is on track to surge by 13 percent as more boomers age into that category.
Unless Trump can reverse his backslide with college-educated whites and seniors, the demographic math will heavily favor Biden winning the White House.