Start off in Michigan and Detroit. Biden actually got about 1,000 fewer votes than Clinton in Detroit. Trump, meanwhile, got nearly 5,000 more votes. Given Trump received so few votes in Detroit, this was good enough for a 65% increase for Trump….Then look at the counties surrounding Wayne County (where Detroit is located) as well as the places in Wayne outside of Detroit. Biden saw a 25% increase in his vote share, while Trump’s vote share increased by just 15%. That alone was worth a net of more than 120,000 votes for Biden’s margin over Trump compared with Clinton and 2016.

As in Detroit, Trump’s been the one who has been disproportionately outperforming his 2016 Philadelphia performance. At this hour, Biden is doing fewer than 5,000 votes better than Clinton in 2016. Trump’s doing more than 20,000 votes better than he did in 2016. That’s about a 20% increase in his vote total in the city….The surrounding suburban counties have been much friendlier to Biden. His margin over Trump is about 80,000 votes more than Clinton’s was in these same counties. The percentage increase for Biden in his vote total (21%) dwarfs Trump’s (11%)….Again, these 80,000 votes were more than enough to overcome Trump’s 2016 statewide margin in Pennsylvania of about 45,000.

Trump’s problem wasn’t Milwaukee. While Biden did pick up votes in the city of Milwaukee compared with Clinton, it was a rather small amount (about 6,000). Trump snagged an additional 3,000 or so votes. Trump’s percentage increase (because he started at such a low baseline) in his vote total of 7% in the city of Milwaukee was actually double that of Biden’s over Clinton’s (3%)….The suburban counties and Milwaukee County outside the city of Milwaukee are where Biden advanced the ball over Trump. Biden’s percentage increase of the vote in these counties (25%) compared with Clinton more than doubled Trump’s (12%). That’s the opposite of what happened in the city of Milwaukee, where Trump’s percentage vote increase was larger than the one on the Democratic side….In vote terms, Biden’s margin in these suburbs improved by about 25,000 compared with Clinton’s….As in Michigan and Pennsylvania, this alone would have wiped out Trump’s 2016 statewide margin. He took Wisconsin by a touch under 23,000 in 2016.

Enten doesn’t address the Georgia flip. But William Frey has noted at Brookings that “Georgia’s urban core counties (including several close-in Atlanta counties that are sometime thought of as suburbs) helped the 2020 result swing toward Democrats. The counties of Fulton, DeKalb, and Clayton have consistently voted Democratic in recent elections….The populous counties of Gwinnett, Cobb, and Henry flipped to voting Democratic in 2016, and increased their Democratic margins even more so this year. Other suburban counties that showed increased Democratic support since 2016 were Douglas, Newton, and Rockdale.”

Enten’s conclusion about Biden’s victory: “The bottom line is that all these numbers make sense and tell a consistent story: Biden won because he was able to build on the traditional Democratic strength in the big cities by expanding his support into the suburban areas right outside of them. There wasn’t any grand conspiracy by big city machines. Trump simply got beat because suburban voters were tired of him.”