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Why Pennsylvania Could Decide The 2020 Election

This is the fourth in a series of articles examining the politics and demographics of 2020’s expected swing states.

Right now, Pennsylvania looks like the single most important state of the 2020 election. According to FiveThirtyEight’s presidential forecast, Pennsylvania is by far the likeliest state to provide either President Trump or Joe Biden with the decisive vote in the Electoral College: It has a 31 percent chance of being the tipping-point state.1 (That’s what happens when you take one of the most evenly divided states in the union and give it 20 electoral votes.) In fact, Pennsylvania is so important that our model gives Trump an 84 percent chance of winning the presidency if he carries the state — and it gives Biden a 96 percent chance of winning if Pennsylvania goes blue.

Few could have guessed that the Keystone State would eventually become the “keystone” of the Electoral College,2 since going into 2016, Pennsylvania had voted for the Democrat in six straight presidential elections. More impressively, Pennsylvania had been more Democratic-leaning than the national popular vote in every presidential election since 1952. But both streaks were snapped in 2016, when Trump carried Pennsylvania by 0.7 percentage points — making it 2.9 points redder than the nation as a whole.

Is Pennsylvania now a Republican-leaning state?

How Pennsylvania has voted relative to the nation as a whole in presidential elections since 1952

Year Dem. GOP Margin Nat’l Margin Penn. Lean
1952 46.9% 52.7% R+5.9 R+10.5 D+4.6
1956 43.3 56.5 R+13.2 R+15.9 D+2.7
1960 51.1 48.7 D+2.3 D+0.2 D+2.1
1964 64.9 34.7 D+30.2 D+22.4 D+7.9
1968 47.6 44.0 D+3.6 R+1.1 D+4.7
1972 39.1 59.1 R+20.0 R+23.0 D+3.0
1976 50.4 47.7 D+2.7 D+2.1 D+0.6
1980 42.5 49.6 R+7.1 R+9.4 D+2.3
1984 46.0 53.3 R+7.4 R+18.0 D+10.7
1988 48.4 50.7 R+2.3 R+7.6 D+5.2
1992 45.1 36.1 D+9.0 D+5.8 D+3.2
1996 49.2 40.0 D+9.2 D+8.5 D+0.7
2000 50.6 46.4 D+4.2 D+0.5 D+3.7
2004 51.0 48.5 D+2.5 R+2.4 D+4.9
2008 54.7 44.3 D+10.3 D+7.3 D+3.1
2012 52.1 46.7 D+5.4 D+3.9 D+1.5
2016 47.9 48.6 R+0.7 D+2.2 R+2.9

Sources: Dave Leip’s Atlas of U.S. Presidential Elections, Pennsylvania Department of State, U.S. House of Representatives

Pennsylvania’s eventual defection shouldn’t have surprised us, though. Non-Hispanic white people without bachelor’s degrees make up 55 percent of Pennsylvania’s population age 25 or older, and Trump accelerated their migration to the Republican Party in 2016. According to the Center for American Progress, the turnout rate among these voters increased from 53.0 percent in 2012 to 57.4 percent in 2016 — and they went from voting for Mitt Romney by 20.3 points to voting for Trump by 28.6 points.

Pennsylvania’s run to the right, however, has been a long time in the making. For much of the 20th century, blue-collar, white Pennsylvanians were considered part of the Democratic base. But the share of workers in Pennsylvania belonging to labor unions (which have historically played a huge role advocating and organizing for Democratic candidates) has fallen from 27.5 percent in 1983 to 12.0 percent in 2019, and many have blamed trade and environmental policies pushed by Democrats for the decline of the state’s manufacturing and mining industries.

Campaigns have also been forced to reconsider their conception of Pennsylvania’s political geography. The conventional wisdom was that western and eastern Pennsylvania were Democratic and central Pennsylvania was solidly Republican (memorably summarized by Democratic strategist James Carville’s quote that, between Pittsburgh and Philadelphia, Pennsylvania was just Alabama). While this may have been true (at least politically) in, say, 2000, working-class western and northeastern Pennsylvania have slowly but surely been getting redder. As a result, Pennsylvania’s new geographic divide is between southeastern Pennsylvania and the rest of the state — in other words, the parts of the state that are culturally Northeastern and the parts that are culturally Midwestern or Appalachian.3

Granted, even this is an oversimplified description of Pennsylvania’s political divide. Pittsburgh’s Allegheny County is one of the few counties in the state that is getting bluer (the Midwest has upper-class suburbs too!). And Philadelphia County actually voted more Republican in 2016, despite having the state’s smallest non-college-educated white population (by percentage). This hints at another problem Democrats would like to solve: returning to their former strength among Black voters. (Philadelphia County is 44 percent Black.) According to CAP, Clinton won “only” 89.8 percent of the Black vote in Pennsylvania. That’s obviously very high, but it’s short of the 96.0 percent that Barack Obama received four years earlier — and those margins matter. If Clinton had matched Obama’s share of the Black vote, CAP found, she would have narrowly carried Pennsylvania in 2016 — even with her poor performance among white voters without a bachelor’s degree.4

Apart from winning back non-college-educated white voters or Black voters, some Democrats may see a third way forward in Pennsylvania: running up their margin in the suburbs. The other trend evident from the map above is that Democrats are gaining ground in the affluent, well-educated counties around Philadelphia. Philly’s four “collar counties” — Bucks, Chester, Delaware and Montgomery — went from voting for Obama by 10 points in 2012 to voting for Clinton by 14 points. But the problem for Democrats is that those four counties contain only 22 percent of Pennsylvania’s 2016 voters, and they are moving to the left far more slowly than the rest of the state is moving to the right. For example, the 24 counties in western Pennsylvania5 other than Allegheny contain a similar 19 percent of Pennsylvania voters, yet they went from voting for Romney by 18 points to voting for Trump by 32 points.

Of course, Democrats don’t have to choose just one group of voters to appeal to. Biden has been making overtures to suburban voters, Black voters and non-college-educated white voters — and there are signs he’s succeeding on multiple fronts. The last two polls (one Democratic, one Republican) to ask about the presidential race in Pennsylvania’s 1st Congressional District — which is almost coterminous with Bucks County — both gave Biden a 9-point lead in a suburban district Clinton carried by only 2 points. And a February poll by Mercyhurst University showed Biden at 48 percent and Trump at 44 percent in post-industrial Erie County, which Trump won by 2 points in 2016 — although Biden’s lead was still a far cry from the 16 points by which Obama carried Erie in 2012. And, in a stroke of luck for Biden, he may be uniquely positioned to reverse some of Democrats’ most severe 2016 losses: the 24 points shaved off the Democratic margin in Lackawanna and Luzerne counties. These counties are the heart of the Scranton/Wilkes-Barre metropolitan area, where Biden was born, grew up and speaks of often on the campaign trail.

All told, Biden currently leads the FiveThirtyEight polling average in Pennsylvania by 4.9 points. Adjusting for demographics and the possibility of change over the next two months, our forecast projects that the Democrat will ultimately carry the Keystone State by 4.6 points. However, both numbers are closer than Biden’s lead nationally, implying that if the overall race tightens, Biden could fall victim to the same trends that made Pennsylvania so inhospitable for Clinton in 2016. In other words, it’s no coincidence that Biden’s 75 in 100 chance of winning Pennsylvania is nearly identical to his chance of winning the election: As goes Pennsylvania, so goes the Electoral College.

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  1. As of Sept. 14 at 5 p.m. Eastern.

  2. Its state nickname derives from the fact that Pennsylvania was the “keystone” among the original 13 colonies, linking the North and South both geographically and politically.

  3. A common debate at FiveThirtyEight is, “Is Pennsylvania in the Midwest or Northeast?” Turns out, it’s in both.

  4. However, Black turnout wasn’t Clinton’s problem. CAP found that African Americans made up only a slightly smaller share of the electorate in 2016 than in 2012, and even if Black turnout had remained steady, it wouldn’t have changed the outcome. How Black voters actually voted was her undoing.

  5. As defined by the federal court system.

Nathaniel Rakich is a senior editor and senior elections analyst at FiveThirtyEight.